Clearer HTML email formatting

In the salutation line of change emails, set the action described in the
message in bold rather than setting the name of the change in bold.

The table below describes use of bold in the salutation of change
emails, with [...] markers to surround the emboldened terms.

 Email Type        | Salutation
 ------------------+----------------------------------------------------
 Abandoned         | $user [abandoned] this change.
 Comment           | $user [posted comments] on this change.
 Delete-Reviewer   | $user [removed $reviewer] from this change.
 Delete-Vote       | $user [removed a vote] from this change.
 Merged            | $user [merged] this change.
 New-Change        | $user would like $reviewer to [review] this change.
 New-change (auto) | $user uploaded this change for [review].
 Replace-Patch-Set | $user [uploaded patch set #$num] to this change.
 Restored          | $user [restored] this change.
 Reverted          | $user [reverted] this change.

Note that the change subject no longer appears in these salutations, as
it is already included in the email subject.

To avoid use of monospace where it is not needed, the approval list in
Merged emails and the cover-letter field for Abandoned and Delete-Vote
emails is set in a proportionate-width font rather than monospaced.
Furthermore, because they are redundant to information already included
in the email, the cover-letter field is removed from Delete-Reviewer and
Restored emails.

Change-Id: Ic96483ebc9eb605d8a330e67952edc69f2b01041

gerrit-server/src/main/resources/com/google/gerrit/server/mail/DeleteVoteHtml.soy

@@ -17,14 +17,13 @@
 {namespace com.google.gerrit.server.mail.template}
 
 /**
- * @param change
  * @param coverLetter
  * @param email
  * @param fromName
  */
 {template .DeleteVoteHtml autoescape="strict" kind="html"}
   <p>
-    {$fromName} removed a vote from <strong>{$change.subject}</strong>.
+    {$fromName} <strong>removed a vote</strong> from this change.
   </p>
 
   {if $email.changeUrl}
@@ -34,6 +33,6 @@
   {/if}
 
   {if $coverLetter}
-    {call .Pre}{param content: $coverLetter /}{/call}
+    <div style="white-space:pre-wrap">{$coverLetter}</div>
   {/if}
 {/template}