fix(bitbucket): source link root path (#32676)

Signed-off-by: Adam Setch <adam.setch@outlook.com>

lib/modules/platform/bitbucket/index.spec.ts

@@ -1656,6 +1656,14 @@ describe('modules/platform/bitbucket/index', () => {
 
       expect(bitbucket.massageMarkdown(prBody)).toMatchSnapshot();
     });
+
+    it('converts source links', () => {
+      const prBody = '[source](https://bitbucket.org/foo/bar/tree/HEAD)';
+
+      expect(bitbucket.massageMarkdown(prBody)).toBe(
+        '[source](https://bitbucket.org/foo/bar/src/HEAD)',
+      );
+    });
   });
 
   describe('updatePr()', () => {

lib/modules/platform/bitbucket/index.ts

@@ -583,6 +583,7 @@ export function massageMarkdown(input: string): string {
     .replace(regEx(/<\/?(details|blockquote)>/g), '')
     .replace(regEx(`\n---\n\n.*?<!-- rebase-check -->.*?\n`), '')
     .replace(regEx(/\]\(\.\.\/pull\//g), '](../../pull-requests/')
+    .replace(regEx(/\/tree\/HEAD/g), '/src/HEAD')
     .replace(regEx(/<!--renovate-(?:debug|config-hash):.*?-->/g), '');
 }