Problem:
When running an initial parse, parse() returns an empty table rather
than an actual range. In `languagetree.lua`, we manually check if
a parse was incremental to determine the changed parse region.

Solution:
- Always return a range (in the C side) from parse().
- Simplify the language tree code a bit.
- Logger no longer shows empty ranges on the initial parse.

Breaking change: `ts_node_child_containing_descendant()` was removed

Breaking change: tree-sitter 0.25 (HEAD) required

Problem:  nlua_call_ref_ctx() does not pop the return value in fast
          context that did not error.
Solution: Fall through to end; calling nlua_call_pop_retval().

Problem:
Calling `xstrdup` with a NULL pointer causes a SIGSEGV if `lua_tostring` returns
NULL in `nlua_luv_thread_common_cfpcall`.

Crash stack trace:
- `_platform_strlen` → `xstrdup` (memory.c:469)
- `nlua_luv_thread_common_cfpcall` (executor.c:281)

Solution:
Check if `lua_tostring` returns NULL and pass NULL to `event_create` to avoid the crash.

**Problem:** Parsing can be slow for large files, and it is a blocking
operation which can be disruptive and annoying.

**Solution:** Provide a function for asynchronous parsing, which accepts
a callback to be run after parsing completes.

Co-authored-by: Lewis Russell <lewis6991@gmail.com>
Co-authored-by: Luuk van Baal <luukvbaal@gmail.com>
Co-authored-by: VanaIgr <vanaigranov@gmail.com>

Problem:  We want to deprecate `nvim_err_write(ln)()` but there is no
          obvious replacement (from Lua). Meanwhile we already have
          `nvim_echo()` with an `opts` argument.
Solution: Add `err` argument to `nvim_echo()` that directly maps to
          `:echoerr`.

Regression from 2a7d0ed6145bf3f8b139c2694563f460f829813a, which removed
header that is only needed if wasmtime support is enabled. Prevent this
from happening again by wrapping the include in a `HAVE_WASMTIME` check.

Result of `make iwyu` (after some "fixups").

Problem:  Two separate try/end wrappers, that only marginally differ by
          restoring a few variables. Wrappers that don't restore
          previous state are dangerous to use in "api-fast" functions.
Solution: Remove wrappers that don't restore the previous state.
          Always use TRY_WRAP.