Text operations

Decided

D-0071, settled by the language’s author: part of spec §18. Older text cites it as 18.71.

One Text trait, implemented for str and String, whose operations are default methods over text(): both get every one, a literal included, with no Deref and no duplicate APIs. Pieces are str views; only replace and the case changes allocate. Parsing takes the whole text and returns an optional, refusing surrounding spaces rather than skipping them, since trim() says that explicitly. Case changes are ASCII only — Unicode case mapping needs tables std does not carry (§14.4)