rgit v2.1.0

Added: rgit show FILE:SYMBOL..., batched symbols/show, symbols --porcelain,
.mdx, and the Rust grammar with rust-analyzer cross-check (closes #1).

Changed: a grouped CSS rule is indexed one anchor per selector.

Fixed: anchors whose name contains a colon, Rust attribute and separator
extents, and pyright blocking multi-line Python bindings.

rgit v2.0.0

Major: `rgit-install -with-servers` is removed. It was documented, shipped
in three releases, and anything scripting it breaks on upgrade.

The release's most consequential fix is in blob synthesis: a container's
first new member was spliced outside the container and committed at exit 0,
producing a blob that does not parse.

Also: `rgit symbols` no longer reads outside the repository; --follow-rename
keeps shebang language detection; a vanished untracked file no longer fails
the whole diff report; the LSP handshake announces workspaceFolders; and the
cross-check comparison is corrected on five counts, taking corpus
disagreements from 2334 to 27 across nine grammars.

Building from source now needs Go 1.27+.