v0.0-537-gfe32ee1: Align groups of data/variable/net declarations inside modules.

Grouping is determined by consecutive data/net declarations
regardless of spacing between declarations.

Columns are sliced similarly to port declarations, respecting packed/unpacked
dimensions.

This logic could be re-used inside other contexts as well.

Does not handle inside `ifdef blocks or conditional/loop generate blocks yet.

Does not align "= expr" initializers yet.

Fixes #358

PiperOrigin-RevId: 327281779