Add tsserver support

test/lsp/test_lsp_client_messages.vader

@@ -127,8 +127,8 @@ Execute(ale#lsp#tsserver_message#Change() should return correct messages):
   \     'file': b:dir . '/foo.ts',
   \     'line': 1,
   \     'offset': 1,
-  \     'endLine': 3,
-  \     'endOffset': 5,
+  \     'endLine': 1073741824,
+  \     'endOffset': 1,
   \     'insertString': "foo()\nbar()\nbaz()",
   \   }
   \ ],
@@ -139,7 +139,7 @@ Execute(ale#lsp#tsserver_message#Geterr() should return correct messages):
 
   AssertEqual
   \ [
-  \   1,
+  \   0,
   \   'ts@geterr',
   \   {
   \     'files': [b:dir . '/foo.ts'],