refactor: integer functions, optimize asserts #34112

refactor(lua): add integer coercion helpers

Add vim._tointeger() and vim._ensure_integer(), including optional base
support, and switch integer-only tonumber()/assert call sites in the Lua
runtime to use them.

This also cleans up related integer parsing in LSP, health, loader, URI,
tohtml, and Treesitter code.

supported by AI

runtime/lua/vim/fs.lua

@@ -790,8 +790,7 @@ function M.abspath(path)
 
   -- Windows allows paths like C:foo/bar, these paths are relative to the current working directory
   -- of the drive specified in the path
-  local cwd = (iswin and prefix:match('^%w:$')) and uv.fs_realpath(prefix) or uv.cwd()
-  assert(cwd ~= nil)
+  local cwd = assert((iswin and prefix:match('^%w:$')) and uv.fs_realpath(prefix) or uv.cwd())
   -- Convert cwd path separator to `/`
   cwd = cwd:gsub(os_sep, '/')