Add Custom PSSA tests for checking Comment Format

[PlagueHO]

One of the comment PR corrections I have to make is to correct code comment format. It would be good if we could add PSSA tests for this. There are a few rules I could look at adding:

1. Check for space after #
2. Check comment is on it's own line
3. Check for multi-line comment being in <# #>

Is this something worth implementing? Are there are lot of repos that have violations of this? I might have some violations in the repos I maintain, and this would cause test failures (because I've opted them to fail on style violations), but I'd rather correct them.

[johlju]

I like seeing tests for these. Could be opt-in for custom rules, so would only affect those that opt-in for that, and should more or less be correct already (meaning should be quick to resolve).

Number 3 should also be on separate rows. Could we also test so the text in the comment block is indented?

<#
    Text...
#>