Fix minor errors/annoyances in email templates

There was some funny syntax in merge request email templates. There was a ! before
the merge request number when there probably should be a #. This may be some carry over
from markdown but should not be in email templates.  There were also some capitalization
discrepancies among the subject lines. For those OCD people out there I standardized the
capitalization. :)
Merge pull request #5571 from bke-drewb/email

Fix minor errors/annoyances in email templates