Strip HTML comments from PR comments pushed to Trac tickets

[garrett-eclipse]

Hello,

Can the incoming posts from Github PRs strip HTML comments so we don't get all the issue template text as can be seen here;
​https://core.trac.wordpress.org/ticket/37134
*The PR entries don't support permalink so scroll down to the most recent as of today May 14th 2020.

Thanks

[garrett-eclipse]

PR submitted shows all the Issue Template comments in the Trac post.

[ocean90]

This should already be the case since [9539] but looks like there are cases which aren’t handled yet.

[dd32]

In 9877:

Trac: Github PRs: Actually filter out HTML comments.

This commit message is longer than the fix.

Amends [9539].
See #5057.
Fixes #5213.