Remove or update bitbucket links (GH-101963)

Since Mercurial removal from bitbucket.org, some links are broken.
They are replaced by github.com or webarchive.org links if available. Otherwise, they are removed.

Co-authored-by: Shantanu <12621235+hauntsaninja@users.noreply.github.com>

test/test_pathlib.py

@@ -1938,7 +1938,7 @@ def test_resolve_common(self):
 
     @os_helper.skip_unless_symlink
     def test_resolve_dot(self):
-        # See https://bitbucket.org/pitrou/pathlib/issue/9/pathresolve-fails-on-complex-symlinks
+        # See http://web.archive.org/web/20200623062557/https://bitbucket.org/pitrou/pathlib/issues/9/
         p = self.cls(BASE)
         self.dirlink('.', join('0'))
         self.dirlink(os.path.join('0', '0'), join('1'))