MDLSITE-6745 mustachelint: Ensure that fatal errors include a source

[andrewnicols]

From: https://tracker.moodle.org/browse/MDLSITE-6745

[stronk7]

I've been reading the Tracker issue and it's not clear for me if this should be considered ready or no. Please, confirm.

No matter of that, a couple of comments about the current patch could be:

• Do we need to amend any bats test (or create a new one) to ensure the new information is correctly being output?
• It seems that this needs a rebase on top of current master.

Ciao :-)

[andrewnicols]

Do we need to amend any bats test (or create a new one) to ensure the new information is correctly being output?

I've added a new test for this.

It seems that this needs a rebase on top of current master.

Done. Only one commit missing /o\

[stronk7]

(have squashed the 2 commits, so it's all together in one now)

[stronk7]

Here we go, used "rebase + merge" coz there was another patch landed mins ago.

Thanks all, ciao :-)