Strip trailing space chars

[royjor2016]

An exception occurred: TaskError: b"b'pywikibot.Error: APIError: titleblacklist-custom-space: \xe2\xa7\xbctitleblacklist-custom-space\xe2\xa7\xbd\n[filekey: 1bej5tmfvivo.w15h2z.9401654.webm;\n sessionkey: 1bej5tmfvivo.w15h2z.9401654.webm;\n invalidparameter: filename;\n servedby: mw-api-ext.codfw.main-6cf6f6bcdc-w7c2z;\n help: See https://commons.wikimedia.org/w/api.php for API usage. Subscribe to the mediawiki-api-announce mailing list at <https://lists.wikimedia.org/postorius/lists/mediawiki-api-announce.lists.wikimedia.org/> for notice of API deprecations and breaking changes.]'"

I got hit by this, I think, because as I typed in my phone I didnt delete the auto inserted space after the last word.