Align constant definitions in nested blocks

[giuinktse7]

The setting align_constant_definitions currently only applies to file-level declarations. Constants inside procedures and nested control-flow blocks remain unaligned.

Note: I may be misunderstanding the intended behavior, but I found the current behavior surprising and believe this is a feature gap. You can just close this PR if the current behavior is intentional.

Cause

The constant alignment map is populated for file.decls, but nested statement lists are not scanned before formatting:

main :: proc() {
      SHORT :: 1
      LONGER_NAME :: 2
}

Fix

Compute constant alignment in the Block_Stmt visitor before calling visit_block_stmts.

All braced bodies ultimately pass through this visitor, so the option now applies consistently inside procedures, if, when, and loop blocks:

main :: proc() {
      SHORT       :: 1
      LONGER_NAME :: 2
}

Verification

Added snapshot coverage for constants inside:

• Procedure bodies
• if blocks
• when blocks
• Loop bodies

The complete odinfmt snapshot suite passes.