[clang-tidy][docs] Fix wrong sphinx link after d9afb8c

There was a copy-paste mistake at the embedded link:
  `clang-tidy/checks/cppcoreguidelines-virtual-class-destructor`
  ->
  `clang-tidy/checks/cppcoreguidelines/virtual-class-destructor`

Sphinx error:
/home/zbebnal/git/llvm-project/clang-tools-extra/docs/ReleaseNotes.rst:168:unknown document: clang-tidy/checks/cppcoreguidelines-virtual-class-destructor

Build bot: https://lab.llvm.org/buildbot#builders/115/builds/29805

Differential Revision: https://reviews.llvm.org/D126891

Author: Balazs Benics

clang-tools-extra/docs/ReleaseNotes.rst

@@ -166,7 +166,7 @@ Changes in existing checks
   the check would try to create another initializer for the same member.
 
 - Fixed a false positive in :doc:`cppcoreguidelines-virtual-class-destructor
-  <clang-tidy/checks/cppcoreguidelines-virtual-class-destructor>` involving
+  <clang-tidy/checks/cppcoreguidelines/virtual-class-destructor>` involving
   ``final`` classes. The check will not diagnose classes marked ``final``, since
   those cannot be used as base classes, consequently, they can not violate the
   rule.