diagnose: add to command-list.txt

Add 'git diagnose' as an "ancilliaryinterrogator" (like 'git bugreport') to
'command-list.txt' in order to have it show up in 'git help -a' and avoid
the "no link" warning message from the 'check-docs' Makefile target.

Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

command-list.txt

@@ -91,6 +91,7 @@ git-cvsimport                           foreignscminterface
 git-cvsserver                           foreignscminterface
 git-daemon                              synchingrepositories
 git-describe                            mainporcelain
+git-diagnose                            ancillaryinterrogators
 git-diff                                mainporcelain           info
 git-diff-files                          plumbinginterrogators
 git-diff-index                          plumbinginterrogators