Allow custom error messages for regex issues

extensions/json/server/src/json-toolbox/jsonSchema.ts

@@ -39,6 +39,8 @@ export interface IJSONSchema {
 	not?:IJSONSchema;
 	enum?:any[];
 	format?: string;
+	
+	errorMessage?:string; // VS code internal
 }
 
 export interface IJSONSchemaMap {

extensions/json/server/src/jsonParser.ts

@@ -452,7 +452,7 @@ export class StringASTNode extends ASTNode {
 			if (!regex.test(this.value)) {
 				validationResult.warnings.push({
 					location: { start: this.start, end: this.end },
-					message: nls.localize('patternWarning', 'String does not match the pattern of "{0}"', schema.pattern)
+					message: schema.errorMessage || nls.localize('patternWarning', 'String does not match the pattern of "{0}"', schema.pattern)
 				});
 			}
 		}