key: apply ValueMapper to substituted reference values (go-ini#382)

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Fix parsing of double-quoted values with backslash continuations (go-…

…ini#373)

Co-authored-by: ᴊᴏᴇ ᴄʜᴇɴ <jc@unknwon.io>

ini: allow changing the default section name (go-ini#319)

parser: fix line skipping when key is empty (go-ini#323)

write: pretty print section only if it is not the last one (go-ini#321)

Co-authored-by: Joe Chen <jc@unknwon.io>

key: ignore empty values in `ValueWithShadows` (go-ini#316)

Return an empty array from `ValueWithShadows` if there is none (go-in…

…i#313)

Co-authored-by: Joe Chen <jc@unknwon.io>

Fix nested values can span sections (go-ini#306)

Fix python multiline EOF error (go-ini#309)

file: add `HasSection` method (go-ini#308)

Co-authored-by: Joe Chen <jc@unknwon.io>