enh(protobuf) Support multiline comments (#2597)

Author: Paxa

CHANGES.md

@@ -47,6 +47,7 @@ Language Improvements:
 - enh(dart) Add `late` and `required` keywords, and `Never` built-in type (#2550) [Sam Rawlins][]
 - enh(erlang) Add underscore separators to numeric literals (#2554) [Sergey Prokhorov][]
 - enh(handlebars) Support for sub-expressions, path-expressions, hashes, block-parameters and literals (#2344) [Nils Knappmeier][]
+- enh(protobuf) Support multiline comments (#2597) [Pavel Evstigneev][]
 
 [Josh Goebel]: https://github.com/yyyc514
 [Peter Plantinga]: https://github.com/pplantinga
@@ -60,6 +61,7 @@ Language Improvements:
 [Martin (Lhoerion)]: https://github.com/Lhoerion
 [Jim Mason]: https://github.com/RocketMan
 [lioshi]: https://github.com/lioshi
+[Pavel Evstigneev]: https://github.com/Paxa
 
 
 ## Version 10.0.2

src/languages/protobuf.js

@@ -19,6 +19,7 @@ export default function(hljs) {
       hljs.QUOTE_STRING_MODE,
       hljs.NUMBER_MODE,
       hljs.C_LINE_COMMENT_MODE,
+      hljs.C_BLOCK_COMMENT_MODE,
       {
         className: 'class',
         beginKeywords: 'message enum service', end: /\{/,

test/markup/protobuf/message-message.expect.txt

@@ -1,7 +1,13 @@
+<span class="hljs-comment">// A Container message</span>
 <span class="hljs-class"><span class="hljs-keyword">message</span> <span class="hljs-title">Container</span> </span>{
   <span class="hljs-class"><span class="hljs-keyword">message</span> <span class="hljs-title">Message</span> </span>{
     <span class="hljs-keyword">required</span> <span class="hljs-built_in">int64</span> id = <span class="hljs-number">1</span>;
   }
   <span class="hljs-keyword">repeated</span> Message messages = <span class="hljs-number">1</span>;
   <span class="hljs-keyword">optional</span> <span class="hljs-built_in">int32</span> number = <span class="hljs-number">2</span>;
 }
+
+<span class="hljs-comment">/*
+  test multiline
+  comment
+*/</span>

test/markup/protobuf/message-message.txt

@@ -1,7 +1,13 @@
+// A Container message
 message Container {
   message Message {
     required int64 id = 1;
   }
   repeated Message messages = 1;
   optional int32 number = 2;
 }
+
+/*
+  test multiline
+  comment
+*/