py3: avoid iterating over a literal bytes in highlight

In Python 3, iterating over a bytes literal yields integers. Since we
use the value in `text.replace()`, this fails on Python 3 with the
following trackback:

    Traceback (most recent call last):
      File "/usr/lib/python3/dist-packages/mercurial/hgweb/hgwebdir_mod.py", line 378, in run_wsgi
        for r in self._runwsgi(req, res):
      File "/usr/lib/python3/dist-packages/mercurial/hgweb/hgweb_mod.py", line 326, in run_wsgi
        for r in self._runwsgi(req, res, repo):
      File "/usr/lib/python3/dist-packages/mercurial/hgweb/hgweb_mod.py", line 449, in _runwsgi
        return getattr(webcommands, cmd)(rctx)
      File "/usr/lib/python3/dist-packages/mercurial/hgweb/webcommands.py", line 211, in file
        return _filerevision(web, webutil.filectx(web.repo, web.req))
      File "/usr/lib/python3/dist-packages/hgext/highlight/__init__.py", line 72, in filerevision_highlight
        pygmentize(web, b'fileline', fctx, web.tmpl)
      File "/usr/lib/python3/dist-packages/hgext/highlight/__init__.py", line 58, in pygmentize
        field, fctx, style, tmpl, guessfilenameonly=filenameonly
      File "/usr/lib/python3/dist-packages/hgext/highlight/highlight.py", line 62, in pygmentize
        text = text.replace(c, b'')
    TypeError: a bytes-like object is required, not 'int'

hgext/highlight/highlight.py

@@ -1,101 +1,101 b''
 # highlight.py - highlight extension implementation file
 #
 #  Copyright 2007-2009 Adam Hupp <[e-mail]> and others
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 #
 # The original module was split in an interface and an implementation
 # file to defer pygments loading and speedup extension setup.
 
 from __future__ import absolute_import
 
 from mercurial import demandimport
 
 demandimport.IGNORES.update([b'pkgutil', b'pkg_resources', b'__main__'])
 
 from mercurial import (
     encoding,
     pycompat,
 )
 
 from mercurial.utils import stringutil
 
 with demandimport.deactivated():
     import pygments
     import pygments.formatters
     import pygments.lexers
     import pygments.plugin
     import pygments.util
 
     for unused in pygments.plugin.find_plugin_lexers():
         pass
 
 highlight = pygments.highlight
 ClassNotFound = pygments.util.ClassNotFound
 guess_lexer = pygments.lexers.guess_lexer
 guess_lexer_for_filename = pygments.lexers.guess_lexer_for_filename
 TextLexer = pygments.lexers.TextLexer
 HtmlFormatter = pygments.formatters.HtmlFormatter
 
 SYNTAX_CSS = (
     b'\n<link rel="stylesheet" href="{url}highlightcss" type="text/css" />'
 )
 
 
 def pygmentize(field, fctx, style, tmpl, guessfilenameonly=False):
 
     # append a <link ...> to the syntax highlighting css
     tmpl.load(b'header')
     old_header = tmpl.cache[b'header']
     if SYNTAX_CSS not in old_header:
         new_header = old_header + SYNTAX_CSS
         tmpl.cache[b'header'] = new_header
 
     text = fctx.data()
     if stringutil.binary(text):
         return
 
     # str.splitlines() != unicode.splitlines() because "reasons"
-    for c in b"\x0c\x1c\x1d\x1e":
+    for c in b"\x0c", b"\x1c", b"\x1d", b"\x1e":
         if c in text:
             text = text.replace(c, b'')
 
     # Pygments is best used with Unicode strings:
     # <http://pygments.org/docs/unicode/>
     text = text.decode(pycompat.sysstr(encoding.encoding), 'replace')
 
     # To get multi-line strings right, we can't format line-by-line
     try:
         path = pycompat.sysstr(fctx.path())
         lexer = guess_lexer_for_filename(path, text[:1024], stripnl=False)
     except (ClassNotFound, ValueError):
         # guess_lexer will return a lexer if *any* lexer matches. There is
         # no way to specify a minimum match score. This can give a high rate of
         # false positives on files with an unknown filename pattern.
         if guessfilenameonly:
             return
 
         try:
             lexer = guess_lexer(text[:1024], stripnl=False)
         except (ClassNotFound, ValueError):
             # Don't highlight unknown files
             return
 
     # Don't highlight text files
     if isinstance(lexer, TextLexer):
         return
 
     formatter = HtmlFormatter(nowrap=True, style=pycompat.sysstr(style))
 
     colorized = highlight(text, lexer, formatter)
     coloriter = (
         s.encode(pycompat.sysstr(encoding.encoding), 'replace')
         for s in colorized.splitlines()
     )
 
     tmpl._filters[b'colorize'] = lambda x: next(coloriter)
 
     oldl = tmpl.cache[field]
     newl = oldl.replace(b'line|escape', b'line|colorize')
     tmpl.cache[field] = newl