refactor(lsp): unify capability checks and registration #36781

Problem:
Our LSP type system didnt have a concept of RegistrationMethods, this is where the method to dynamically register for a capability is sent to a different method endpoint then is used to call it. Eg `textDocument/semanticTokens` rather than the specific full/range/delta methods

Solution:
Extended generator to create `vim.lsp.protocol.Methods.Registration` with these registration methods. Also extend `_request_name_to_client_capability` to cover these methods. Adjust typing to suit

runtime/lua/vim/lsp/protocol.lua

@@ -1149,6 +1149,12 @@ protocol.Methods = {
   workspace_workspaceFolders = 'workspace/workspaceFolders',
 }
 
+-- Generated by gen_lsp.lua, keep at end of file.
+--- LSP registration methods
+---@alias vim.lsp.protocol.Method.Registration
+--- | 'notebookDocument/sync'
+--- | 'textDocument/semanticTokens'
+
 -- stylua: ignore start
 -- Generated by gen_lsp.lua, keep at end of file.
 --- Maps method names to the required client capability
@@ -1290,6 +1296,7 @@ protocol._request_name_to_server_capability = {
   ['workspace/willDeleteFiles'] = { 'workspace', 'fileOperations', 'willDelete' },
   ['workspace/willRenameFiles'] = { 'workspace', 'fileOperations', 'willRename' },
   ['workspace/workspaceFolders'] = { 'workspace', 'workspaceFolders' },
+  ['textDocument/semanticTokens'] = { 'semanticTokensProvider' },
 }
 -- stylua: ignore end