demandimport: convert ignored modules from bytes -> str in extensions

The default list of ignored modules are str, and test for bypassing the lazy
import is `module.__name__ in ignores`, so these were effectively NOT ignored.
Most of these date back to the grand byteification in 687b865b95ad, with some
subsequent additions that followed the existing example.

I have no idea if these modules in fact need to bypass lazy importing, but at
least it follows the intent of the code.

hgext/convert/bzr.py

@@ -23,9 +23,9 b' from . import common'
 # these do not work with demandimport, blacklist
 demandimport.IGNORES.update(
     [
-        b'breezy.transactions',
-        b'breezy.urlutils',
-        b'ElementPath',
+        'breezy.transactions',
+        'breezy.urlutils',
+        'ElementPath',
     ]
 )
 

hgext/highlight/highlight.py

@@ -11,7 +11,7 b''
 
 from mercurial import demandimport
 
-demandimport.IGNORES.update([b'pkgutil', b'pkg_resources', b'__main__'])
+demandimport.IGNORES.update(['pkgutil', 'pkg_resources', '__main__'])
 
 from mercurial import (
     encoding,