Add links to GH issues in 6.2.1 release notes (#3769)

* add MAD page

* link to GitHub issues in release notes known issues

* update templates for 6.2.1

* Revert "add MAD page"

This reverts commit 9cce72bba3.

* update wordlist for spellcheck linter

* add rccl note

* update rocal version change heading to be more obvious

* make rocal note more specific

* fix missing space

* fix capitalization

.wordlist.txt

@@ -53,6 +53,7 @@ CSC
 CSE
 CSV
 CSn
+CTest
 CTests
 CU
 CUDA
@@ -387,6 +388,7 @@ UAC
 UC
 UCC
 UCX
+UE
 UIF
 UMC
 USM
@@ -653,6 +655,7 @@ quasirandom
 queueing
 rccl
 rdc
+rdma
 reStructuredText
 redirections
 refactorization