Send translation comment notifications to more users

[mathjazz]

Locale managers should always receive notifications for translation comments. That's particularly important when a comment is added to a translation that doesn't have an author.

Should we also send notifications to translators? @flodolo?

For reference, translation comment notifications are sent to significantly less users than team comment notifications:

pontoon/pontoon/base/views.py

Lines 476 to 502 in a6195e4

	def _send_add_comment_notifications(user, comment, entity, locale, translation):
	# On translation comment, notify:
	# - authors of other translation comments in the thread
	# - translation author
	# - translation reviewers
	if translation:
	recipients = set(translation.comments.values_list("author__pk", flat=True))
	if translation.user:
	recipients.add(translation.user.pk)
	if translation.approved_user:
	recipients.add(translation.approved_user.pk)
	if translation.unapproved_user:
	recipients.add(translation.unapproved_user.pk)
	if translation.rejected_user:
	recipients.add(translation.rejected_user.pk)
	if translation.unrejected_user:
	recipients.add(translation.unrejected_user.pk)
	# On team comment, notify:
	# - project-locale translators or locale translators
	# - locale managers
	# - authors of other team comments in the thread
	# - authors of translation comments
	# - translation authors
	# - translation reviewers
	else:

[flodolo]

Sounds like sending to both translators and managers makes sense.

We will need to also update this doc.