fix(metadata): preserve underscores in generated anchor IDs (#749)

The DOC_API_SLUGS_REPLACEMENTS regex was converting underscores to
dashes, breaking internal links across the Node.js docs

Author: thisalihassan

src/generators/metadata/constants.mjs

@@ -6,7 +6,7 @@ export const IGNORE_STABILITY_STEMS = ['documentation'];
 export const DOC_API_SLUGS_REPLACEMENTS = [
   { from: /node.js/i, to: 'nodejs' }, // Replace Node.js
   { from: /&/, to: '-and-' }, // Replace &
-  { from: /[/_,:;\\ ]/g, to: '-' }, // Replace /_,:;\. and whitespace
+  { from: /[/,:;\\ ]/g, to: '-' }, // Replace /,:;\. and whitespace
   { from: /^-+(?!-*$)/g, to: '' }, // Remove any leading hyphens
   { from: /(?<!^-*)-+$/g, to: '' }, // Remove any trailing hyphens
   { from: /^(?!-+$).*?(--+)/g, to: '-' }, // Replace multiple hyphens

src/generators/metadata/utils/__tests__/slugger.test.mjs

@@ -25,8 +25,8 @@ describe('slug', () => {
   });
 
   describe('special character to hyphen replacement', () => {
-    it('replaces underscores with hyphens', () => {
-      assert.strictEqual(slug('foo_bar', identity), 'foo-bar');
+    it('preserves underscores', () => {
+      assert.strictEqual(slug('foo_bar', identity), 'foo_bar');
     });
 
     it('replaces forward slashes with hyphens', () => {
@@ -85,8 +85,8 @@ describe('slug', () => {
       assert.strictEqual(slug('Hello World'), 'hello-world');
     });
 
-    it('converts underscored names to hyphenated slugs', () => {
-      assert.strictEqual(slug('child_process'), 'child-process');
+    it('preserves underscores in module names', () => {
+      assert.strictEqual(slug('child_process'), 'child_process');
     });
 
     it('handles titles with no special characters', () => {