test: fix `internet/test-inspector-help-page`

The webpage at the URL referenced by node --inspect was retitled when it was recently moved.

Update the test to match the new title "Debugging Node.js" (formerly "Debugging Guide").

Refs: https://github.com/nodejs/nodejs.org/pull/6265

---

Internet tests are not run on regular PR CI's -- they are run daily both on:

• Jenkins, as part of the node-daily-* CI jobs
• GitHub Actions, via the Test internet workflow.

Without this PR, the test currently fails:

=== release test-inspector-help-page ===
Path: internet/test-inspector-help-page
node:assert:1035
    throw err;
    ^

AssertionError [ERR_ASSERTION]: The input did not match the regular expression />Debugging Guide</. Input: