schemes: use br'' literal to define bytes regexp

hgext/schemes.py

@@ -63,7 +63,7 b' command = cmdutil.command(cmdtable)'
 # leave the attribute unspecified.
 testedwith = 'ships-with-hg-core'
 
-_partre = re.compile(r'\{(\d+)\}'.encode(u'latin1'))
+_partre = re.compile(br'\{(\d+)\}')
 
 class ShortRepository(object):
     def __init__(self, url, scheme, templater):