Add html_utf8 content type. (#2423)

CHANGES.md

@@ -1,6 +1,8 @@
 # Changes
 
 ## Unreleased - 2021-xx-xx
+### Changed
+* `ContentType::html` now returns `Content-Type: text/html; charset=utf-8` instead of `Content-Type: text/html`.
 
 
 ## 4.0.0-beta.10 - 2021-10-20

src/http/header/content_type.rs

@@ -60,52 +60,53 @@ crate::http::header::common_header! {
 }
 
 impl ContentType {
-    /// A constructor  to easily create a `Content-Type: application/json`
+    /// A constructor to easily create a `Content-Type: application/json`
     /// header.
     #[inline]
     pub fn json() -> ContentType {
         ContentType(mime::APPLICATION_JSON)
     }
 
-    /// A constructor  to easily create a `Content-Type: text/plain;
+    /// A constructor to easily create a `Content-Type: text/plain;
     /// charset=utf-8` header.
     #[inline]
     pub fn plaintext() -> ContentType {
         ContentType(mime::TEXT_PLAIN_UTF_8)
     }
 
-    /// A constructor  to easily create a `Content-Type: text/html` header.
+    /// A constructor to easily create a `Content-Type: text/html; charset=utf-8`
+    /// header.
     #[inline]
     pub fn html() -> ContentType {
-        ContentType(mime::TEXT_HTML)
+        ContentType(mime::TEXT_HTML_UTF_8)
     }
 
-    /// A constructor  to easily create a `Content-Type: text/xml` header.
+    /// A constructor to easily create a `Content-Type: text/xml` header.
     #[inline]
     pub fn xml() -> ContentType {
         ContentType(mime::TEXT_XML)
     }
 
-    /// A constructor  to easily create a `Content-Type:
+    /// A constructor to easily create a `Content-Type:
     /// application/www-form-url-encoded` header.
     #[inline]
     pub fn form_url_encoded() -> ContentType {
         ContentType(mime::APPLICATION_WWW_FORM_URLENCODED)
     }
 
-    /// A constructor  to easily create a `Content-Type: image/jpeg` header.
+    /// A constructor to easily create a `Content-Type: image/jpeg` header.
     #[inline]
     pub fn jpeg() -> ContentType {
         ContentType(mime::IMAGE_JPEG)
     }
 
-    /// A constructor  to easily create a `Content-Type: image/png` header.
+    /// A constructor to easily create a `Content-Type: image/png` header.
     #[inline]
     pub fn png() -> ContentType {
         ContentType(mime::IMAGE_PNG)
     }
 
-    /// A constructor  to easily create a `Content-Type:
+    /// A constructor to easily create a `Content-Type:
     /// application/octet-stream` header.
     #[inline]
     pub fn octet_stream() -> ContentType {