Tweak type inference for `const` operands in inline asm
Previously these would be treated like integer literals and default to `i32` if a type could not be determined. To allow for forward-compatibility with `str` constants in the future, this PR changes type inference to use an unbound type variable instead.
The actual type checking is deferred until after typeck where we still ensure that the final type for the `const` operand is an integer type.
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Mention Register Size in `#[warn(asm_sub_register)]`
Fixes#121593
Displays the register size information obtained from `suggest_modifier()` and `default_modifier()`.
The `asm!` and `global_asm!` macros require their operands to appear
strictly in the following order:
- Template strings
- Positional operands
- Named operands
- Explicit register operands
- `clobber_abi`
- `options`
This is overly strict and can be inconvienent when building complex
`asm!` statements with macros. This PR relaxes the ordering requirements
as follows:
- Template strings must still come before all other operands.
- Positional operands must still come before named and explicit register
operands.
- Named and explicit register operands can be freely mixed.
- `options` and `clobber_abi` can appear in any position.
