CVE-2022-29546: OutOfMemory Exception by specifically crafted processing instruction in NekoHtml Parser

The vulnerability stems from improper input termination handling in the processing instruction parsing logic. The commit diff shows the critical fix in HTMLScanner.java's scanPI() method, where a missing EOF check (-1) allowed infinite buffer growth. The added test case 'invalidProcessingInstruction' demonstrates how malformed PI input (<?a/) triggers this condition. The function's loop structure and buffer append operation directly correlate with uncontrolled memory consumption described in CWE-400.