Promotes the six changelog.d fragments into a `## [0.10.0]` section:
sb-ao6l, sb-d65, sb-y4oa, sb-ht2e, sb-vjeg and sb-qqs4, grouped Added 6
/ Changed 6 / Fixed 3. Every fragment bullet is carried over byte for
byte; the prose written here is the lead paragraph and the `[0.10.0]`
link reference.

sb-e77s shipped no fragment and needs none. It documents the host-tab
and drawer seams in their own moduledocs, which the changelog.d README
excludes by name as work a caller of the public API cannot see.

Bumps the version to 0.10.0 in mix.exs, in the compiler's
`@compiler_version`, and in the README's install pin - the same three
places c35c02b bumped for 0.9.0. The compiler identity assertion reads
the version relationally, so no test moves.

Not tagged and not published: `mix hex.build` was run as proof and its
tarball deleted.

Refs: sb-g2bu