Found by @MattParkerDev

When I added source mapping for component tags, I completely forgot about end tags, so they're not mapped. I don't believe we can map the end tags, because we require source mappings and line pragmas to match exactly, so we probably need to just handle this in tooling. It should be pretty easy though.

Take this hover example:

When hovering over the start component tag, we map to C# and hover shows results from Roslyn. When hovering over the end tag we get the Razor hover result which is different (and worse). Same for Go To Definition and Find All References I imagine.

We can solve this by just detecting that we're being asked to Hover/GTD/FAR on an end tag, and pretend we're on the start tag instead, before calling Roslyn.