feat(parsers): rework tiers

* stable: updates follow semver releases (todo)
* unstable: updates follow HEAD (default)
* unmaintained: no automatic updates
* unsupported: no updates, cannot be installed

lua/nvim-treesitter/_meta/parsers.lua

@@ -35,7 +35,7 @@ error('Cannot require a meta file')
 ---List of other languages to install (e.g., if queries inherit from them)
 ---@field requires? string[]
 ---
----Language support tier, maps to "core", "stable", "community", "unmaintained"
+---Language support tier, maps to "stable", "unstable", "unmaintained", "unsupported"
 ---@field tier integer
 ---
 ---Explanatory footnote text to add in SUPPORTED_LANGUAGES.md

lua/nvim-treesitter/config.lua

@@ -1,6 +1,6 @@
 local M = {}
 
-M.tiers = { 'stable', 'core', 'community', 'unsupported' }
+M.tiers = { 'stable', 'unstable', 'unmaintained', 'unsupported' }
 
 ---@class TSConfig
 ---@field ensure_install string[]
@@ -10,7 +10,7 @@ M.tiers = { 'stable', 'core', 'community', 'unsupported' }
 ---@type TSConfig
 local config = {
   ensure_install = {},
-  ignore_install = { 'unsupported' },
+  ignore_install = {},
   install_dir = vim.fs.joinpath(vim.fn.stdpath('data'), 'site'),
 }