Fix bug in page:Debugging (broken links)

[michaelwooley]

Fixes #16860

[michaelwooley]

Hmm.. unrelated test failure (i.e. unit tests unrelated to docs). It looks like #16863 ran into the same issues, albeit on more browsers.

Let me know if there's anything I can do to troubleshoot.

---

(representative failure)

======================================================================
FAIL: test_fetch_sync_xhr (test_browser.browser)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/root/project/tests/common.py", line 1486, in run_browser
    self.assertContained(expectedResult, output)
  File "/root/project/tests/common.py", line 846, in assertContained
    additional_info
  File "/usr/lib/python3.6/unittest/case.py", line 670, in fail
    raise self.failureException(msg)
AssertionError: Expected to find '/report_result?exit:0
' in '[no http server activity]
', diff:

--- expected
+++ actual
@@ -1 +1 @@
-/report_result?exit:0
+[no http server activity]



During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/root/project/tests/test_browser.py", line 149, in decorated
    return f(self, *args, **kwargs)
  File "/root/project/tests/test_browser.py", line 4616, in test_fetch_sync_xhr
    self.btest_exit('fetch/sync_xhr.cpp', args=['-sFETCH_DEBUG', '-sFETCH', '-sUSE_PTHREADS', '-sPROXY_TO_PTHREAD'])
  File "/root/project/tests/common.py", line 1649, in btest_exit
    return self.btest(filename, *args, **kwargs)
  File "/root/project/tests/common.py", line 1686, in btest
    self.run_browser(outfile + url_suffix, message, ['/report_result?' + e for e in expected], timeout=timeout, extra_tries=extra_tries)
  File "/root/project/tests/common.py", line 1491, in run_browser
    return self.run_browser(html_file, message, expectedResult, timeout, extra_tries - 1)
  File "/root/project/tests/common.py", line 1493, in run_browser
    raise e
  File "/root/project/tests/common.py", line 1486, in run_browser
    self.assertContained(expectedResult, output)
  File "/root/project/tests/common.py", line 846, in assertContained
    additional_info
AssertionError: Expected to find '/report_result?exit:0
' in '[no http server activity]
', diff:

--- expected
+++ actual
@@ -1 +1 @@
-/report_result?exit:0
+[no http server activity]

[kripken]

Thanks!

[kripken]

Looks like that test failure is a random firefox issue that sometimes happens. As this just affects docs it can't be related.