fix(csharp) Support digit separators(highlightjs#4258)

CHANGES.md

@@ -21,6 +21,7 @@ Core Grammars:
 - fix(diff) fix unified diff hunk header regex to allow unpaired numbers [Chris Wilson][]
 - enh(php) support single line and hash comments in attributes, constructor and functions [Antoine Musso][]
 - enh(json) add json5 support [Kerry Shetline][]
+- fix(csharp) Support digit separators [te-ing][]
 
 Documentation:
 
@@ -46,6 +47,7 @@ CONTRIBUTORS
 [Kerry Shetline]: https://github.com/kshetline
 [Twineee1]: https://github.com/Twineee1
 [hbgl]: https://github.com/hbgl
+[te-ing]: https://github.com/te-ing
 
 
 ## Version 11.11.1

src/languages/csharp.js

@@ -166,7 +166,7 @@ export default function(hljs) {
     variants: [
       { begin: '\\b(0b[01\']+)' },
       { begin: '(-?)\\b([\\d\']+(\\.[\\d\']*)?|\\.[\\d\']+)(u|U|l|L|ul|UL|f|F|b|B)' },
-      { begin: '(-?)(\\b0[xX][a-fA-F0-9\']+|(\\b[\\d\']+(\\.[\\d\']*)?|\\.[\\d\']+)([eE][-+]?[\\d\']+)?)' }
+      { begin: '(-?)(\\b0[xX][a-fA-F0-9\'_]+|(\\b[\\d\'_]+(\\.[\\d\'_]*)?|\\.[\\d\'_]+)([eE][-+]?[\\d\'_]+)?)' }
     ],
     relevance: 0
   };

test/markup/csharp/floats.expect.txt

@@ -1,4 +1,6 @@
 <span class="hljs-built_in">float</span> test = <span class="hljs-number">1.0f</span>;
 <span class="hljs-built_in">float</span> test2 = <span class="hljs-number">1.f</span>;
 <span class="hljs-built_in">float</span> test3 = <span class="hljs-number">1.0</span>;
-<span class="hljs-built_in">float</span> test4 = <span class="hljs-number">1</span>;
+<span class="hljs-built_in">float</span> test4 = <span class="hljs-number">1</span>;
+<span class="hljs-built_in">float</span> test5 = <span class="hljs-number">1_000</span>;
+

test/markup/csharp/floats.txt

@@ -1,4 +1,5 @@
 float test = 1.0f;
 float test2 = 1.f;
 float test3 = 1.0;
-float test4 = 1;
+float test4 = 1;
+float test5 = 1_000;