docs: Add more details to CONTRIBUTING.md (#1339)

Signed-off-by: Sheng Chen <sheche@microsoft.com>

.vscode/launch.json

@@ -27,7 +27,8 @@
       "cwd": "${workspaceFolder}/gradle-server",
       "presentation": {
         "group": "debug",
-        "order": 2
+        "order": 2,
+        "hidden": true
       }
     },
     {

CONTRIBUTING.md

@@ -21,8 +21,19 @@ Running the build for the first time can take a bit of time, but subsequent buil
 
 The extension uses a Gradle plugin (`com.microsoft.gradle.GradlePlugin`) to get a lot of information from your project's Gradle build. If you want to debug the Gradle plugin, you can follow these steps:
 
-1. Run vscode launch configuration `Debug Extension & Gradle Plugin`
-2. Run vscode launch configuration `Attach to Gradle Plugin`
+1. Run vscode launch configuration `Debug Extension & Gradle Plugin`.
+2. Run vscode launch configuration `Attach to Gradle Plugin`.
+
+> Note: There is a known issue that when the Gradle project stores in a sub-folder of the root folder, the `Attach to Gradle Plugin` will fail to attach. See [#1237](https://github.com/microsoft/vscode-gradle/issues/1237).
+
+## Debugging Gradle Language Server (editing feature related)
+
+1. Run vscode launch configuration `Debug Language Server: Launch Extension`.
+2. Run vscode launch configuration `Debug Language Server: Launch Language Server`.
+
+## Debugging Gradle Server (work with Gradle daemon)
+
+Run vscode launch configuration `Debug Server & Extension`.
 
 ## Development Workflow