Fix error propagation all the way out of processStringSync.

packages/string-templates/src/index.ts

@@ -231,7 +231,11 @@ export function processStringSync(
       return process(string)
     }
   } catch (err: any) {
-    return input
+    const { noThrow = true } = opts
+    if (noThrow) {
+      return input
+    }
+    throw err
   }
 }