`ArrayType` does not have a const `capacity`

[Polygonalr]

Reference:

gccrs/gcc/rust/typecheck/rust-tyty.h

Lines 1196 to 1198 in b9e349a

	// FIXME: I dont think this should be in tyty - tyty should already be const
	// evaluated
	HIR::Expr &capacity_expr;

Working on SlicePattern type checking at the moment, though due to this issue, checking the size of a SlicePattern against the capacity of ArrayType parent is currently not possible. Example of such a check in rustc: https://play.rust-lang.org/?version=stable&mode=debug&edition=2024&gist=4caaa75fdc97f88d45be6bf054ff1171

Will edit this issue to point to my SlicePattern type checking changes w/o size checking once my PR for that is ready and merged.