Replace P_AproxDistance with FixedHypot, and replace FixedHypot's algorithm with R_PointToDist2's

Port of KartKrew/Kart-Public!243 (merged) that also replaces every instance of P_AproxDistance in the code, instead of turning it into a macro for FixedHypot. When P_AproxDistance is used in Lua, generates a deprecated warning to use FixedHypot instead!

Inspired by the work seen in !1232 (merged) and !1309 (merged).

changed the description

merged

mentioned in commit 83947d44

Didn't even realise this MR was up until now, but doesn't FixedHypot have worse problems with integer overflows than P_AproxDistance does?

Yeah, it does iirc.

this also replaced FixedHypot with R_PointToDist2's algorithm which doesn't have the overflow issues