[torque-ls] add option to trace communication from client

Bug: v8:8880
Change-Id: I835c465ccb63bcc20e9ec9cafda153a49de2bf7d
Reviewed-on: https://chromium-review.googlesource.com/c/1497010Reviewed-by: Simon Zünd <szuend@chromium.org>
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60010}

tools/torque/vscode-torque/package.json

@@ -37,7 +37,17 @@
                     "type": "string",
                     "default": "torque-log.txt",
                     "description": "Target file for language server logging output"
-                }
+                },
+                "torque.trace.server": {
+                    "type": "string",
+                    "enum": [
+                      "off",
+                      "messages",
+                      "verbose"
+                    ],
+                    "default": "off",
+                    "description": "Trace the communication with the Torque language server from VSCode."
+                  }  
             }
         },
         "languages": [