Simplify the logic for retrieving the injection ranges for the language
tree. The trees are now also sorted by starting position, regardless of
whether they are part of a combined injection or not. This would be
helpful if ranges are ever to be stored in an interval tree or other
kind of sorted tree structure.

Re-enable these after release.

Problem: Cannot disable individual captures and patterns in treesitter queries.

Solution: 
* Expose the corresponding tree-sitter API functions for `TSQuery` object. 
* Add documentation for `TSQuery`.
* Return the pattern ID from `get_captures_at_pos()` (and hence `:Inspect!`).

Problem: No way to check the version of a treesitter parser.

Solution: Add version metadata (ABI 15 parsers only) as well as parser state count and supertype information (ABI 15) in `vim.treesitter.language.inspect()`. Also graduate the `abi_version` field, as this is now the official upstream name.

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Co-authored-by: Christian Clason <c.clason@uni-graz.at>

Problem:
Indenting text is a common task in plugins/scripts for
presentation/formatting, yet vim has no way of doing it (especially
"dedent", and especially non-buffer text).

Solution:
Introduce `vim.text.indent()`. It sets the *exact* indentation because
that's a more difficult (and thus more useful) task than merely
"increasing the current indent" (which is somewhat easy with a `gsub()`
one-liner).

TSHighlighter now places marks for conceal_lines metadata. A new
internal decor provider callback _on_conceal_line was added that
instructs the highlighter to place conceal_lines marks whenever the
editor needs to know whether a line is concealed. The bundled markdown
queries use conceal_lines metadata to conceal code block fence lines.

* refactor: rewrite test without trailing whitespace

* test: combined injection tests

Co-authored-by: Jaehwang Jung <tomtomjhj@gmail.com>