Change for Pull Request Titles Referencing Bugzilla Issues (prepping for Bugzilla to GitHub migration)

[Mike Parker]

In preparation for the Bugzilla to GitHub migration, the DLang 
bot has been updated to change how it handles references to 
Bugzilla issues. From now on, when you submit a PR that 
references a Bugzilla issue, the title should include "Fix 
Bugzilla" rather than "Fix Issue".

https://github.com/dlang/dlang-bot/pull/302

Thanks to Vladimir and Robert for pushing this forward.