Ensure to strip any code block annotation after language name

Some markdown files can contain extra code block annotations after
the language name, separated by commas.

Such extra annotations break code highlighting after processing
by showdown-highlight as the language name ends up invalid and
cannot be found by highlight.js.

So ensure to strip these extra annotations to fix HTML rendering.

Author: anlambert

lib/index.js

@@ -51,10 +51,15 @@ module.exports = function showdownHighlight({ pre = false, auto_detection = true
         const replacement = (wholeMatch, match, left, right) => {
             match = decodeHtml(match)
 
-            const lang = (left.match(/class=\"([^ \"]+)/) || [])[1]
+            let lang = (left.match(/class=\"([^ \"]+)/) || [])[1]
 
             if (!lang && !auto_detection) {
                 return wholeMatch
+            } else if (lang && lang.indexOf(',') > 0) {
+                // ensure to strip any code block annotation after language
+                const langNoAnnotation = lang.slice(0, lang.indexOf(','));
+                left = left.replace(new RegExp(lang, 'g'), langNoAnnotation);
+                lang = langNoAnnotation;
             }
 
             if (left.includes(classAttr)) {

package.json

@@ -54,6 +54,7 @@
     "obedm503 (https://obedm503.github.io)",
     "Ariel Shaqed (Scolnicov) (https://github.com/arielshaqed)",
     "Bruno de Araújo Alves (devbaraus) (https://github.com/devbaraus)",
-    "Sekyu Kwon <[email protected]> (https://github.com/Phryxia)"
+    "Sekyu Kwon <[email protected]> (https://github.com/Phryxia)",
+    "Antoine Lambert <[email protected]> (https://github.com/anlambert)"
   ]
 }

test/index.js

@@ -12,14 +12,21 @@ function sayHello (msg, who) {
     return \`\${who} says: msg\`;
 }
 sayHello("Hello World", "Johnny");
-
 \`\`\``
+
     const CODEBLOCK_WITHOUT_LANGUAGE = `
 \`\`\`
 function sayHello (msg, who) {
     return \`\${who} says: msg\`;
 }
 sayHello("Hello World", "Johnny");
+\`\`\``
+
+    const CODEBLOCK_WITH_LANGUAGE_AND_ANNOTATION = `
+\`\`\`rust,no_run
+fn do_amazing_thing() -> i32 {
+   unimplemented!()
+}
 \`\`\``
 
     // After requiring the module, use it as extension
@@ -42,6 +49,12 @@ sayHello("Hello World", "Johnny");
         t.expect(html.includes('class="hljs"')).toEqual(true);
     });
 
+    t.should("work with code block language and annotation", () => {
+        let html = converter.makeHtml(CODEBLOCK_WITH_LANGUAGE_AND_ANNOTATION);
+        t.expect(html.includes('class="hljs rust language-rust"')).toEqual(true);
+        t.expect(html.includes("hljs-type")).toEqual(true);
+    });
+
     const converter_auto_disabled = new showdown.Converter({
         extensions: [showdownHighlight({
             auto_detection: false