gh-137586: Register chromium, opera, microsoft-edge in register_standard_browsers on macOS

These browsers were present in MacOSX._BUNDLE_IDS but not registered,
causing webbrowser.get("opera") etc. to raise Error: could not locate
runnable browser.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: secengjeff

Lib/webbrowser.py

@@ -493,8 +493,11 @@ def register_standard_browsers():
     if sys.platform == 'darwin':
         register("MacOSX", None, MacOSX('default'))
         register("chrome", None, MacOSX('google chrome'))
+        register("chromium", None, MacOSX('chromium'))
         register("firefox", None, MacOSX('firefox'))
         register("safari", None, MacOSX('safari'))
+        register("opera", None, MacOSX('opera'))
+        register("microsoft-edge", None, MacOSX('microsoft edge'))
         # macOS can use below Unix support (but we prefer using the macOS
         # specific stuff)