extensions: recommend against using wrapfunction for repo methods
Instead, all extensions should use the "dynamic subclass" trick:
subclass repo.__class__ and then replace repo.__class__ with your new
subclass. This avoids conflicts that happen when one extension uses
wrapfunction and another uses subclassing to extend the same method of
localrepository.
http://example.com/no/anchor, branches: (None, [])
http://example.com/an/anchor, branches: ('foo', [])
http://example.com/no/anchor/branches, branches: (None, ['foo'])
http://example.com/an/anchor/branches, branches: ('bar', ['foo'])
http://example.com/an/anchor/branches-None, branches: ('foo', [])