This reverts commit 2a7cb32959b4c616bd2c76ae1933f8e068e391ad.

This commit changes `languagetree.lua` so that it creates a scratch
buffer under the hood when dealing with string parsers. This will make
it much easier to just use extmarks whenever we need to track injection
trees in `languagetree.lua`. This also allows us to remove the
`treesitter.c` code for parsing a string directly.

Note that the string parser's scratch buffer has `set noeol nofixeol` so
that the parsed source exactly matches the passed in string.

Problem: `TSLangInfo` annotation does not reflect the structure returned
by `vim.treesitter.language.inspect()`.

Solution: Move version information under new (optional since ABI 15 only)
`TSLangMetadata` field.

Remove the `set_timeout` functions for `TSParser` and instead add a timeout
parameter to the regular parse function. Remove these deprecated tree-sitter
API functions and replace them with the preferred `TSParseOptions` style.

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:** The documentation for `TSNode` and `TSTree` methods is
incomplete from the LSP perspective. This is because they are written
directly to the vimdoc, rather than in Lua and generated to vimdoc.

**Solution:** Migrate the docs to Lua and generate them into the vimdoc.
This requires breaking up the `treesitter/_meta.lua` file into a
directory with a few different modules.

This commit also makes the vimdoc generator slightly more robust with
regard to sections that have multiple help tags (e.g. `*one* *two*`)