jj: Change log finding alias to case insensitive

Since 612b92d1 we are matching private commits case insensitively, we
should also match default commit search insensitively by default.

This changes the alias to search without caring for the case. We do not
have an equivalent alias for case sensitive search, and I will only add
one if I need the specificity often enough to warrant an extra alias.

vcs/jj/config/sh/alias.d/jj.sh

@@ -57,7 +57,7 @@ alias jloo="jj log --patch"
 alias JLOO="jj log --patch -r 'all()'"
 alias jol="jj op log"
 jlf() {
-    jj log -r "description(\"$*\")"
+    jj log -r "description(substring-i:\"$*\")"
 }
 jlof() {
     jj log --summary -r "description($*)"