Add tooltip with issuable title to note references
Description
Currently, if you hover over a reference to an issue/MR, after a small wait (I think it might be performing a request?) a small native tooltip will appear with the title of the issue/MR. I find this really handy when trying to maintain context when talking about multiple issues/MRs.
Trouble is, it's slow, this is why I think it may be performing a request. If not, even better.
Proposal
Use bootstrap tooltips to display these issuable titles and persist the issuable title alongside the issuable link when rendering the reference.
Seeing as these references are GFM, I assume we can render the reference with extra attributes, data-toggle="tooltip" data-placement="bottom" title="issuable_title"