replace resolveLocation with a simpler implementation

[43081j]

resolveLocation has been left alone for quite some time because its already so delicate.

though it turns out @stramel discovered many of our errors are reported with the wrong position information and tests didn't catch this as they either had no end column, or we just didn't check that the asserted column actually was the right one! 🤦‍♂️

nobody understood this function and i struggled to remember too, so i deleted it.

i've rewritten it from scratch based on offsets, with getLocFromIndex being our saviour here 🥳 this means we don't need to calculate line changes, account for multi-line expressions, quasis, etc. that was where most of the complexity lived before.

here's how we calculate it now:

• Loop through the quasis
• Every time we see an expression, increment a correction number by how long the placeholder is for that expression
• Increment the HTML start offset by the correction number
• Increment the HTML end offset by the correction number
• Convert the indices to source locations
• If we ever get into some funky situation where a range or something is null, we resolve to the whole quasi's location as a fallback

cc @stramel

FYI i have commented the function a fair amount to help explain it

[stramel]

LGTM

Tested it out in a project:

[43081j]

ill try add some tests before we merge but that looks great, thanks a lot for checking it in an editor