[GithubIssueBridge] Fix notice with reviews (#2589)
[GithubIssueBridge] Fix notice with reviews (#2589)

Some timeline items, like review threads and the first comment on PRs,
have no header, so this handles the first comment and adds a generic
title if that doesn't work.
ORelio/rss-bridge,Riduidel/rss-bridge,Riduidel/rss-bridge,ORelio/rss-bridge,ORelio/rss-bridge,RSS-Bridge/rss-bridge,Riduidel/rss-bridge,RSS-Bridge/rss-bridge,RSS-Bridge/rss-bridge