feat(ccls): add CclsSwitchSourceHeader

ccls 0.20241108 has added support for the extension from clangd.

lua/lspconfig/configs/ccls.lua

@@ -1,5 +1,25 @@
 local util = require 'lspconfig.util'
 
+local function switch_source_header(bufnr)
+  bufnr = util.validate_bufnr(bufnr)
+  local client = util.get_active_client_by_name(bufnr, 'ccls')
+  local params = { uri = vim.uri_from_bufnr(bufnr) }
+  if client then
+    client.request('textDocument/switchSourceHeader', params, function(err, result)
+      if err then
+        error(tostring(err))
+      end
+      if not result then
+        print 'Corresponding file cannot be determined'
+        return
+      end
+      vim.api.nvim_command('edit ' .. vim.uri_to_fname(result))
+    end, bufnr)
+  else
+    print 'method textDocument/switchSourceHeader is not supported by any servers active on the current buffer'
+  end
+end
+
 return {
   default_config = {
     cmd = { 'ccls' },
@@ -12,6 +32,14 @@ return {
     -- ccls does not support sending a null root directory
     single_file_support = false,
   },
+  commands = {
+    CclsSwitchSourceHeader = {
+      function()
+        switch_source_header(0)
+      end,
+      description = 'Switch between source/header',
+    },
+  },
   docs = {
     description = [[
 https://github.com/MaskRay/ccls/wiki