diff --git a/CHANGES.md b/CHANGES.md
index 0c9a70812..733f28ca7 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -15,7 +15,7 @@
 * Public field of `web::Query` has been made private. [#1894]
 
 [#1891]: https://github.com/actix/actix-web/pull/1891
-[#????]: https://github.com/actix/actix-web/pull/????
+[#1894]: https://github.com/actix/actix-web/pull/1894
 
 ## 4.0.0-beta.1 - 2021-01-07
 ### Added
diff --git a/src/responder.rs b/src/responder.rs
index b0292ed0d..9b33ac81a 100644
--- a/src/responder.rs
+++ b/src/responder.rs
@@ -110,7 +110,7 @@ impl<T: Responder> Responder for (T, StatusCode) {
 impl Responder for &'static str {
     fn respond_to(self, _: &HttpRequest) -> HttpResponse {
         HttpResponse::Ok()
-            .content_type("text/plain; charset=utf-8")
+            .content_type(mime::TEXT_PLAIN_UTF_8)
             .body(self)
     }
 }
@@ -118,7 +118,7 @@ impl Responder for &'static str {
 impl Responder for &'static [u8] {
     fn respond_to(self, _: &HttpRequest) -> HttpResponse {
         HttpResponse::Ok()
-            .content_type("application/octet-stream")
+            .content_type(mime::APPLICATION_OCTET_STREAM)
             .body(self)
     }
 }
@@ -126,7 +126,7 @@ impl Responder for &'static [u8] {
 impl Responder for String {
     fn respond_to(self, _: &HttpRequest) -> HttpResponse {
         HttpResponse::Ok()
-            .content_type("text/plain; charset=utf-8")
+            .content_type(mime::TEXT_PLAIN_UTF_8)
             .body(self)
     }
 }
@@ -134,7 +134,7 @@ impl Responder for String {
 impl<'a> Responder for &'a String {
     fn respond_to(self, _: &HttpRequest) -> HttpResponse {
         HttpResponse::Ok()
-            .content_type("text/plain; charset=utf-8")
+            .content_type(mime::TEXT_PLAIN_UTF_8)
             .body(self)
     }
 }
@@ -142,7 +142,7 @@ impl<'a> Responder for &'a String {
 impl Responder for Bytes {
     fn respond_to(self, _: &HttpRequest) -> HttpResponse {
         HttpResponse::Ok()
-            .content_type("application/octet-stream")
+            .content_type(mime::APPLICATION_OCTET_STREAM)
             .body(self)
     }
 }
@@ -150,7 +150,7 @@ impl Responder for Bytes {
 impl Responder for BytesMut {
     fn respond_to(self, _: &HttpRequest) -> HttpResponse {
         HttpResponse::Ok()
-            .content_type("application/octet-stream")
+            .content_type(mime::APPLICATION_OCTET_STREAM)
             .body(self)
     }
 }
diff --git a/src/types/either.rs b/src/types/either.rs
index 229ad69a0..d72a14fd0 100644
--- a/src/types/either.rs
+++ b/src/types/either.rs
@@ -1,5 +1,4 @@
 //! For either helper, see [`Either`].
-// TODO: could we just use either::Either?
 
 use bytes::Bytes;
 use futures_util::{future::LocalBoxFuture, FutureExt, TryFutureExt};
diff --git a/src/types/form.rs b/src/types/form.rs
index b5bf07596..71680b19a 100644
--- a/src/types/form.rs
+++ b/src/types/form.rs
@@ -1,4 +1,4 @@
-//! For form-urlencoded helper documentation, see [`Form`].
+//! For URL encoded form helper documentation, see [`Form`].
 
 use std::{
     fmt,