ensure startsWith does not go outside string section

src/string-section.ts

@@ -38,7 +38,7 @@ export class StringSection {
   }
 
   public startsWith(prefix: string, offset: number = 0) {
-    return this.#parent.startsWith(prefix, this.#offset + offset);
+    return prefix.length <= (this.#length - offset) && this.#parent.startsWith(prefix, this.#offset + offset);
   }
 
   public substring(beginIndex: number = 0, endIndex: number = this.#length - beginIndex) {