Update getHeadingText helper to exclude HTML comments from returned heading text (fixes #1411).

test/heading-duplicate-content-siblings-only.md

@@ -95,6 +95,12 @@ BB
 
 {MD024:94}
 
+## Headings <!-- that differ -->
+
+## Headings <!-- in comments -->
+
+{MD024:-2}
+
 <!-- markdownlint-configure-file {
   "heading-style": false,
   "no-duplicate-heading": {

test/snapshots/markdownlint-test-scenarios.mjs.md

@@ -15554,6 +15554,19 @@ Generated by [AVA](https://avajs.dev).
             'no-duplicate-heading',
           ],
         },
+        {
+          errorContext: 'Headings',
+          errorDetail: null,
+          errorRange: null,
+          fixInfo: null,
+          lineNumber: 100,
+          ruleDescription: 'Multiple headings with the same content',
+          ruleInformation: 'https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md024.md',
+          ruleNames: [
+            'MD024',
+            'no-duplicate-heading',
+          ],
+        },
         {
           errorContext: 'A',
           errorDetail: null,
@@ -15722,6 +15735,12 @@ Generated by [AVA](https://avajs.dev).
       ␊
       {MD024:94}␊
       ␊
+      ## Headings <!-- that differ -->␊
+      ␊
+      ## Headings <!-- in comments -->␊
+      ␊
+      {MD024:-2}␊
+      ␊
       <!-- markdownlint-configure-file {␊
         "heading-style": false,␊
         "no-duplicate-heading": {␊