chore: enforce no-throw-literal (#32331)

### Reason for this change

As part of #32324 we are enforcing stricter rules on thrown errors.

### Description of changes

Enforce the `no-throw-literal` eslint rule.
Fix the one instance that wasn't compliant yet.

### Description of how you validated changes

Manual testing. Only changed code is in supporting CLI tool.

### Checklist
- [x] My code adheres to the [CONTRIBUTING
GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and
[DESIGN
GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)

----

*By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache-2.0 license*

Author: mrgrain

tools/@aws-cdk/cdk-build-tools/config/eslintrc.js

@@ -47,6 +47,9 @@ module.exports = {
     '@cdklabs/no-invalid-path': [ 'error' ],
     '@cdklabs/promiseall-no-unbounded-parallelism': [ 'error' ],
 
+    // Error handling
+    'no-throw-literal': [ 'error' ],
+
     // Require use of the `import { foo } from 'bar';` form instead of `import foo = require('bar');`
     '@typescript-eslint/no-require-imports': ['error'],
     '@typescript-eslint/indent': ['error', 2],

tools/@aws-cdk/spec2cdk/lib/util/patterned-name.ts

@@ -1,7 +1,7 @@
 export function parsePattern<A extends string>(pattern: string, fields: { [k in A]: unknown }): PatternedString<A> {
   const placeholders = Object.keys(fields);
   if (!placeholders.some((param) => pattern.includes(param))) {
-    throw `Error: --pattern must contain one of [${placeholders.join(', ')}]`;
+    throw new Error(`--pattern must contain one of [${placeholders.join(', ')}]`);
   }
 
   return (values: { [k in A]: string }) => {