src/goLanguageServer.ts: add go.trace.server configuration

This is available by the vscode lsp client library.
We needed to set the client id - the language server client
library to look up <client_id>.trace.server. Chose 'go' as
the client id.

Acceptable values (off, messages, verbose) are from
https://github.com/microsoft/vscode-languageserver-node/blob/b1f6a443efad3d61cf83344589099dab5318ca66/jsonrpc/src/main.ts#L207

Added this setting to package.json to allow the rich setting UI to
display it properly.

Note: this tracing is done by the lsp client, so it may be
different from the server-side logging gopls provides with
-rpc.trace options.

Change-Id: I3e33a16c953c78627e779383bba56d53ae51e8e0
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/232458
Reviewed-by: Rebecca Stambler <[email protected]>

package.json

@@ -1138,6 +1138,16 @@
           },
           "description": "Use this setting to enable/disable experimental features from the language server."
         },
+        "go.trace.server": {
+          "type": "string",
+          "enum": [
+            "off",
+            "messages",
+            "verbose"
+          ],
+          "default": "off",
+          "description": "Trace the communication between VS Code and the Go language server."
+        },
         "go.useGoProxyToCheckForToolUpdates": {
           "type": "boolean",
           "default": true,

src/goLanguageServer.ts

@@ -119,7 +119,8 @@ function buildLanguageClient(config: LanguageServerConfig) {
 		serverOutputChannel = vscode.window.createOutputChannel(config.serverName);
 	}
 	languageClient = new LanguageClient(
-		config.serverName,
+		'go',  // id
+		config.serverName,  // name
 		{
 			command: config.path,
 			args: ['-mode=stdio', ...config.flags],