Add support for Diagnostic log level

Set Start-EditorServices to log only for Diagnostic log level.

Add string enum support for log level so in UserSettings you get a list.

Author: rkeithhill

package.json

@@ -502,8 +502,15 @@
         },
         "powershell.developer.editorServicesLogLevel": {
           "type": "string",
+          "enum": [
+            "Diagnostic",
+            "Verbose",
+            "Normal",
+            "Warning",
+            "Error"
+          ],
           "default": "Normal",
-          "description": "Sets the logging verbosity level for the PowerShell Editor Services host executable.  Valid values are 'Verbose', 'Normal', 'Warning', and 'Error'"
+          "description": "Sets the logging verbosity level for the PowerShell Editor Services host executable.  Valid values are 'Diagnostic', 'Verbose', 'Normal', 'Warning', and 'Error'"
         },
         "powershell.developer.editorServicesWaitForDebugger": {
           "type": "boolean",

scripts/Start-EditorServices.ps1

@@ -44,7 +44,7 @@ param(
     [ValidateNotNullOrEmpty()]
     $LogPath,
 
-    [ValidateSet("Normal", "Verbose", "Error", "Diagnostic")]
+    [ValidateSet("Diagnostic", "Normal", "Verbose", "Error", "Diagnostic")]
     $LogLevel,
 
 	[Parameter(Mandatory=$true)]
@@ -74,7 +74,7 @@ param(
 $minPortNumber = 10000
 $maxPortNumber = 30000
 
-if ($LogLevel -ne "Normal") {
+if ($LogLevel -eq "Diagnostic") {
     $VerbosePreference = 'Continue'
     Start-Transcript (Join-Path (Split-Path $LogPath -Parent) Start-EditorServices.log) -Force
 }

src/logging.ts

@@ -9,6 +9,7 @@ import vscode = require("vscode");
 import utils = require("./utils");
 
 export enum LogLevel {
+    Diagnostic,
     Verbose,
     Normal,
     Warning,
@@ -65,6 +66,10 @@ export class Logger {
         this.writeAtLevel(LogLevel.Normal, message, ...additionalMessages);
     }
 
+    public writeDiagnostic(message: string, ...additionalMessages: string[]) {
+        this.writeAtLevel(LogLevel.Diagnostic, message, ...additionalMessages);
+    }
+
     public writeVerbose(message: string, ...additionalMessages: string[]) {
         this.writeAtLevel(LogLevel.Verbose, message, ...additionalMessages);
     }
@@ -112,8 +117,9 @@ export class Logger {
 
     private logLevelNameToValue(logLevelName: string): LogLevel {
         switch (logLevelName.toLowerCase()) {
-            case "normal": return LogLevel.Normal;
+            case "diagnostic": return LogLevel.Diagnostic;
             case "verbose": return LogLevel.Verbose;
+            case "normal": return LogLevel.Normal;
             case "warning": return LogLevel.Warning;
             case "error": return LogLevel.Error;
             default: return LogLevel.Normal;