textwrap: don't split words at punctuation by default

The default `textwrap::WordSeparator::UnicodeBreakProperties` provides
sensible line breaking for (e.g.) emojis and CJK text. Unfortunately, it
also considers punctuation like `/` to be an appropriate location for
line breaks. This is fine for normal text, but leads to very bad
behavior when attempting to wrap error messages. Here, a file path is
broken across multiple lines (with box drawing characters added in
between parts of the path as well), making it impossible to copy-paste
the path out of the error message:

```
Error:   × Failed to read Buck2 event log from `buck2 build //aaa/aaaa` via /var/folders/z5/fclwwdms3r1gq4k4p3pkvvc00000gn/
  │ T/.tmpBgvlUI/buck-log.jsonl.gz
  ╰─▶ failed to open file `/var/folders/z5/fclwwdms3r1gq4k4p3pkvvc00000gn/T/.tmpBgvlUI/buck-log.jsonl.gz`: No such
      file or directory (os error 2)
```

In the future, we may want to write our own line break algorithm that
breaks between CJK codepoints and emojis but not at punctuation like
slashes. For now, I believe it will be better to break lines at ASCII
spaces only.

Similar changes are made for some other settings:
- The default for `break_words` has been changed to `false` for similar
  reasons.
- The default `textwrap::WordSplitter` has been changed to not split
  words at existing hyphens, to prevent splits like `--foo-bar` into
  `--foo-` and `bar`.

src/handlers/graphical.rs

@@ -1,6 +1,8 @@
 use std::fmt::{self, Write};
 
 use owo_colors::{OwoColorize, Style, StyledList};
+use textwrap::WordSeparator;
+use textwrap::WordSplitter;
 use unicode_width::{UnicodeWidthChar, UnicodeWidthStr};
 
 use crate::diagnostic_chain::{DiagnosticChain, ErrorKind};
@@ -61,7 +63,7 @@ impl GraphicalReportHandler {
             tab_width: 4,
             with_cause_chain: true,
             wrap_lines: true,
-            break_words: true,
+            break_words: false,
             with_primary_span_start: true,
             word_separator: None,
             word_splitter: None,
@@ -83,7 +85,7 @@ impl GraphicalReportHandler {
             wrap_lines: true,
             with_cause_chain: true,
             with_primary_span_start: true,
-            break_words: true,
+            break_words: false,
             word_separator: None,
             word_splitter: None,
             highlighter: MietteHighlighter::default(),
@@ -262,16 +264,16 @@ impl GraphicalReportHandler {
         if let Some(footer) = &self.footer {
             writeln!(f)?;
             let width = self.termwidth.saturating_sub(2);
-            let mut opts = textwrap::Options::new(width)
+            let opts = textwrap::Options::new(width)
                 .initial_indent("  ")
                 .subsequent_indent("  ")
-                .break_words(self.break_words);
+                .break_words(self.break_words)
-            if let Some(word_separator) = self.word_separator {
+                .word_separator(self.word_separator.unwrap_or(WordSeparator::AsciiSpace))
-                opts = opts.word_separator(word_separator);
+                .word_splitter(
-            }
+                    self.word_splitter
-            if let Some(word_splitter) = self.word_splitter.clone() {
+                        .clone()
-                opts = opts.word_splitter(word_splitter);
+                        .unwrap_or(WordSplitter::NoHyphenation),
-            }
+                );
 
             writeln!(f, "{}", self.wrap(footer, opts))?;
         }
@@ -340,16 +342,16 @@ impl GraphicalReportHandler {
         let initial_indent = format!("  {} ", severity_icon.style(severity_style));
         let rest_indent = format!("  {} ", self.theme.characters.vbar.style(severity_style));
         let width = self.termwidth.saturating_sub(2);
-        let mut opts = textwrap::Options::new(width)
+        let opts = textwrap::Options::new(width)
             .initial_indent(&initial_indent)
             .subsequent_indent(&rest_indent)
-            .break_words(self.break_words);
+            .break_words(self.break_words)
-        if let Some(word_separator) = self.word_separator {
+            .word_separator(self.word_separator.unwrap_or(WordSeparator::AsciiSpace))
-            opts = opts.word_separator(word_separator);
+            .word_splitter(
-        }
+                self.word_splitter
-        if let Some(word_splitter) = self.word_splitter.clone() {
+                    .clone()
-            opts = opts.word_splitter(word_splitter);
+                    .unwrap_or(WordSplitter::NoHyphenation),
-        }
+            );
 
         writeln!(f, "{}", self.wrap(&diagnostic.to_string(), opts))?;
 
@@ -386,16 +388,16 @@ impl GraphicalReportHandler {
                 )
                 .style(severity_style)
                 .to_string();
-                let mut opts = textwrap::Options::new(width)
+                let opts = textwrap::Options::new(width)
                     .initial_indent(&initial_indent)
                     .subsequent_indent(&rest_indent)
-                    .break_words(self.break_words);
+                    .break_words(self.break_words)
-                if let Some(word_separator) = self.word_separator {
+                    .word_separator(self.word_separator.unwrap_or(WordSeparator::AsciiSpace))
-                    opts = opts.word_separator(word_separator);
+                    .word_splitter(
-                }
+                        self.word_splitter
-                if let Some(word_splitter) = self.word_splitter.clone() {
+                            .clone()
-                    opts = opts.word_splitter(word_splitter);
+                            .unwrap_or(WordSplitter::NoHyphenation),
-                }
+                    );
 
                 match error {
                     ErrorKind::Diagnostic(diag) => {
@@ -428,17 +430,16 @@ impl GraphicalReportHandler {
         if let Some(help) = diagnostic.help() {
             let width = self.termwidth.saturating_sub(2);
             let initial_indent = "  help: ".style(self.theme.styles.help).to_string();
-            let mut opts = textwrap::Options::new(width)
+            let opts = textwrap::Options::new(width)
                 .initial_indent(&initial_indent)
                 .subsequent_indent("        ")
-                .break_words(self.break_words);
+                .break_words(self.break_words)
-            if let Some(word_separator) = self.word_separator {
+                .word_separator(self.word_separator.unwrap_or(WordSeparator::AsciiSpace))
-                opts = opts.word_separator(word_separator);
+                .word_splitter(
-            }
+                    self.word_splitter
-            if let Some(word_splitter) = self.word_splitter.clone() {
+                        .clone()
-                opts = opts.word_splitter(word_splitter);
+                        .unwrap_or(WordSplitter::NoHyphenation),
-            }
+                );
-
             writeln!(f, "{}", self.wrap(&help.to_string(), opts))?;
         }
         Ok(())
@@ -489,16 +490,16 @@ impl GraphicalReportHandler {
                     .style(severity_style)
                     .to_string();
 
-                    let mut opts = textwrap::Options::new(width)
+                    let opts = textwrap::Options::new(width)
                         .initial_indent(&initial_indent)
                         .subsequent_indent(&rest_indent)
-                        .break_words(self.break_words);
+                        .break_words(self.break_words)
-                    if let Some(word_separator) = self.word_separator {
+                        .word_separator(self.word_separator.unwrap_or(WordSeparator::AsciiSpace))
-                        opts = opts.word_separator(word_separator);
+                        .word_splitter(
-                    }
+                            self.word_splitter
-                    if let Some(word_splitter) = self.word_splitter.clone() {
+                                .clone()
-                        opts = opts.word_splitter(word_splitter);
+                                .unwrap_or(WordSplitter::NoHyphenation),
-                    }
+                        );
 
                     let mut inner = String::new();