build: strip YAML fontmatter from breaking changes in changelog

---
type: pre_commit_static_analysis_report
description: Results of running static analysis checks when committing changes.
report:
  - task: lint_filenames
    status: passed
  - task: lint_editorconfig
    status: passed
  - task: lint_markdown
    status: na
  - task: lint_package_json
    status: na
  - task: lint_repl_help
    status: na
  - task: lint_javascript_src
    status: passed
  - task: lint_javascript_cli
    status: na
  - task: lint_javascript_examples
    status: na
  - task: lint_javascript_tests
    status: na
  - task: lint_javascript_benchmarks
    status: na
  - task: lint_python
    status: na
  - task: lint_r
    status: na
  - task: lint_c_src
    status: na
  - task: lint_c_examples
    status: na
  - task: lint_c_benchmarks
    status: na
  - task: lint_c_tests_fixtures
    status: na
  - task: lint_shell
    status: na
  - task: lint_typescript_declarations
    status: na
  - task: lint_typescript_tests
    status: na
  - task: lint_license_headers
    status: passed
---

Author: Planeshifter

lib/node_modules/@stdlib/_tools/changelog/generate/lib/breaking_changes.js

@@ -1,4 +1,3 @@
-
 /**
 * @license Apache-2.0
 *
@@ -33,10 +32,44 @@ var heading = require( './heading.js' );
 // VARIABLES //
 
 var STDLIB_GITHUB_URL = 'https://github.com/stdlib-js/stdlib/commit';
+var RE_YAML_DELIMITER = /^\s*---\s*$/;
 
 
 // FUNCTIONS //
 
+/**
+* Strips YAML frontmatter blocks from text.
+*
+* @private
+* @param {string} text - text to process
+* @returns {string} text without YAML blocks
+*/
+function stripYamlBlocks( text ) {
+	var result;
+	var inYaml;
+	var lines;
+	var i;
+
+	lines = text.split( '\n' );
+	result = [];
+	inYaml = false;
+
+	for ( i = 0; i < lines.length; i++ ) {
+		// Check for YAML delimiter (---) with optional whitespace:
+		if ( RE_YAML_DELIMITER.test( lines[i] ) ) {
+			inYaml = !inYaml; // Toggle YAML block state
+			continue;
+		}
+
+		// Only include lines that are not part of YAML blocks:
+		if ( !inYaml ) {
+			result.push( lines[i] );
+		}
+	}
+
+	return trim( result.join( '\n' ) );
+}
+
 /**
 * Formats a breaking change.
 *
@@ -54,9 +87,13 @@ var STDLIB_GITHUB_URL = 'https://github.com/stdlib-js/stdlib/commit';
 * // returns '-   [`abcdef1`](https://github.com/stdlib-js/stdlib/commit/abcdef1234567890): beep'
 */
 function formatBreakingChange( note ) {
-	var parts = note.text.split( '\n' );
-	var hash = trim( note.hash );
-	var out = '-   [`'+hash.substring( 0, 7 )+'`]('+STDLIB_GITHUB_URL+'/'+hash+'): '+parts[ 0 ];
+	var parts;
+	var hash;
+	var out;
+
+	parts = stripYamlBlocks( note.text ).split( '\n' );
+	hash = trim( note.hash );
+	out = '-   [`'+hash.substring( 0, 7 )+'`]('+STDLIB_GITHUB_URL+'/'+hash+'): '+parts[ 0 ];
 	if ( parts.length > 1 ) {
 		out +='\n\n';
 		out += '    -   ';