7030: Support labels in reference search r=matklad a=Veykril
Implements general navigation for labels, goto def, rename and gives labels their own semantic highlighting class.
Fixes#6966
Co-authored-by: Lukas Wirth <lukastw97@gmail.com>
6921: Higher-ranked trait bounds for where clauses r=flodiebold a=Veykril
There is a slight problem with this which is also noted in a FIXME now but `LifetimeParameters` of these ForLifetime where clauses allocate the lifetimes in the corresponding arena as if they were lifetimes of the item itself and not just the clause they belong to. I wasn't entirely sure what I could do about this but given nothing really uses lifetimes like that currently I figured it might be fine? Open to suggestions for that problem.
Co-authored-by: Lukas Wirth <lukastw97@gmail.com>
