docs(__load_completion): note bash version needing dir source avoidance

Author: scop

bash_completion

@@ -2558,7 +2558,8 @@ __load_completion()
         [[ -d $dir ]] || continue
         for compfile in "$cmd" "$cmd.bash" "_$cmd"; do
             compfile="$dir/$compfile"
-            # Avoid trying to source dirs; https://bugzilla.redhat.com/903540
+            # Avoid trying to source dirs as long as we support bash < 4.3
+            # to avoid an fd leak; https://bugzilla.redhat.com/903540
             if [[ -d $compfile ]]; then
                 # Do not warn with . or .. (especially the former is common)
                 [[ $compfile == */.?(.) ]] ||