Promotes the two changelog.d fragments into a `## [0.11.0]` section:
sb-0xqe and sb-6edf, grouped Added 4. Every fragment bullet is carried
over byte for byte; the prose written here is the lead paragraph and
the `[0.11.0]` link reference.

Minor, not patch: both fragments are Added-only, so the release is two
additive public surfaces over 0.10.0 with nothing changed or removed.

Bumps the version to 0.11.0 in mix.exs, in the compiler's
`@compiler_version`, and in the README's install pin - the same three
places 5c45f9b bumped for 0.10.0. The compiler identity assertion reads
the version relationally, so no test moves.

Not tagged and not published, and no hex task was run: the operator
tags and publishes after the campaign wrap. The full gate is the proof
in its place.

Refs: sb-q0bl