Update pylint msg-template to show human-friendly error symbols. Fixes microsoft#382

Author: jcdyer

package.json

@@ -1170,7 +1170,7 @@
 				},
 				"python.linting.pylintArgs": {
 					"type": "array",
-					"description": "Arguments passed in. Each argument is a separate item in the array.",
+					"description": "Arguments passed in. Each argument is a separate item in the array. --msg-template is set by VSCode and cannot be overridden here.",
 					"default": [],
 					"items": {
 						"type": "string"

src/client/linters/pylint.ts

@@ -11,7 +11,7 @@ export class Linter extends baseLinter.BaseLinter {
     }
 
     protected async runLinter(document: TextDocument, cancellation: CancellationToken): Promise<baseLinter.ILintMessage[]> {
-        const messages = await this.run(['--msg-template=\'{line},{column},{category},{msg_id}:{msg}\'', '--reports=n', '--output-format=text', document.uri.fsPath], document, cancellation);
+        const messages = await this.run(['--msg-template=\'{line},{column},{category},{msg_id}:{msg} ({symbol})\'', '--reports=n', '--output-format=text', document.uri.fsPath], document, cancellation);
         messages.forEach(msg => {
             msg.severity = this.parseMessagesSeverity(msg.type, this.pythonSettings.linting.pylintCategorySeverity);
         });