Fix usage hint in a regex comment

Change-Id: If6c748a3e67dc96d5a19c414c5ba592c496dce1a
---
M pywikibot/textlib.py
1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/pywikibot/textlib.py b/pywikibot/textlib.py
index e8e0af3..d7e2366 100644
--- a/pywikibot/textlib.py
+++ b/pywikibot/textlib.py
@@ -86,7 +86,8 @@
 # and correctly matches the end of the file link if the wikilink contains
 # [[ or ]].
 # The namespace names must be substituted into this regex.
-# e.g. FILE_LINK_REGEX % 'File' or FILE_LINK_REGEX % '|'.join(site.namespaces)
+# e.g. FILE_LINK_REGEX % 'File'
+# or FILE_LINK_REGEX % '|'.join(site.namespaces[6])
 FILE_LINK_REGEX = r"""
     \[\[\s*
     (?:%s)  # namespace aliases

