fix test

Author: ajafff

rules/preferWhileRule.ts

@@ -1,7 +1,7 @@
 import * as ts from 'typescript';
 import * as Lint from 'tslint';
 
-const FAIL_MESSAGE = `use while loop instead`;
+const FAIL_MESSAGE = 'Prefer `while` loops instead of `for` loops without an initializer and incrementor.';
 
 export class Rule extends Lint.Rules.AbstractRule {
     public apply(sourceFile: ts.SourceFile): Lint.RuleFailure[] {

test/rules/prefer-while/default/test.ts.lint

@@ -16,4 +16,4 @@ for (i = 1; --i;);
 
 for (i = 1; i, --i);
 
-[fail]: use while loop instead
+[fail]: Prefer `while` loops instead of `for` loops without an initializer and incrementor.