Fix some false positives in the the bookmark checker.

 - Don't check if the fragment is invalid.
 - Don't check it it's empty (`<a href="#">` links to the top of the page).
 - Percent decode the fragment before checking.

[SVN r59137]

tools/inspect

@@ -1 +1 @@
-Subproject commit 0b726aeefbcd3b227d1b263727e44105acf01a3b
+Subproject commit b92edeecd2cb5835b62b6c5991dcefd1e890031a