Add a 'show problem' command which finds one issue or wiki page which matches a single word search term

> Common problems usually have a bug already raised, but maybe the person (often a newbie) doesn't know the right keyword to search on.

> The intent is to ensure that common problems have a single unique well known keyword for them.
This should work roughly like the bugzilla alias feature.
We can append one or more unique keywords to the issue title to emulate this feature.
The cobot command should report an error if multiple there are multiple hits, maybe including a github search link that shows the multiple hits.

> But some problem are user problems, and for those a link to a wiki page would be better, so ideally those are also searched.

> Use issue/wiki title search only if possible, or preference issues with a match in the title.

Ported from old cobot repo, opened by @jayvdb - https://gitlab.com/coala/cobot/issues/74

Start by locating the cobot command entry point and the GitHub issue/wiki search entry points, then compare the requested behavior with the linked GitLab issue. Done means a single-word search reports one matching issue or wiki page and reports multiple matches as described.

Written by the indexing model from the issue text.