smol-toml: Quadratic-time parse() from parseKey rescanning to end of document on each key line

Summary parse has a quadratic-time path in parseKey, reachable on default options with ordinary valid input. For every key line and table-header line, parseKey dist/struct.js, lines 58 and 86 finds the dotted-key separator with ctx.s.indexOf'.', ctx.p, where ctx.s is the whole document. When a ke...