feat!: track parser revision in Lua

Problem: Tracking parser revision in lockfile and allowing override
through the parsers module complicates the code. In addition, only
revision changes are handled robustly, not changes to other installation
info.

Solution: Track parser revision in the parsers module directly. Reload
parser table on every install or update call. Support modifying parser
table in a `User TSUpdate` autocommand.

scripts/update-parsers.lua

@@ -0,0 +1,65 @@
+#!/usr/bin/env -S nvim -l
+vim.opt.runtimepath:append('.')
+local util = require('nvim-treesitter.util')
+local parsers = require('nvim-treesitter.parsers')
+
+local jobs = {} ---@type table<string,vim.SystemObj>
+local updates = {} ---@type string[]
+
+-- check for new revisions
+for k, p in pairs(parsers) do
+  if p.tier < 5 and p.install_info then
+    print('Updating ' .. k)
+    jobs[k] = vim.system({ 'git', 'ls-remote', p.install_info.url })
+  end
+
+  if #vim.tbl_keys(jobs) % 100 == 0 or next(parsers, k) == nil then
+    for name, job in pairs(jobs) do
+      local stdout = vim.split(job:wait().stdout, '\n')
+      jobs[name] = nil
+
+      local info = parsers[name].install_info
+      assert(info)
+
+      local branch = info.branch
+      local line = 1
+      if branch then
+        for j, l in ipairs(stdout) do
+          if l:find(vim.pesc(branch)) then
+            line = j
+            break
+          end
+        end
+      end
+
+      local sha = vim.split(stdout[line], '\t')[1]
+      if info.revision ~= sha then
+        info.revision = sha
+        updates[#updates + 1] = name
+      end
+    end
+  end
+end
+
+assert(#vim.tbl_keys(jobs) == 0)
+
+if #updates > 0 then
+  -- write new parser file
+  local header = '---@type nvim-ts.parsers\nreturn '
+  local parser_file = header .. vim.inspect(parsers)
+  if vim.fn.executable('stylua') == 1 then
+    parser_file = vim.system({ 'stylua', '-' }, { stdin = parser_file }):wait().stdout --[[@as string]]
+  end
+  util.write_file('lua/nvim-treesitter/parsers.lua', parser_file)
+
+  local update_list = table.concat(updates, ', ')
+  print(string.format('\nUpdated parsers: %s', update_list))
+  -- pass list to workflow
+  if os.getenv('GITHUB_ENV') then
+    local env = io.open(os.getenv('GITHUB_ENV'), 'a')
+    env:write(string.format('UPDATED_PARSERS=%s\n', update_list))
+    env:close()
+  end
+else
+  print('\nAll parsers up to date!')
+end