Update ssh.completion.sh to be case-insensitive (#645)

completions/ssh: identify Host/Hostname directives case-insensitively

Co-authored-by: Koichi Murase <myoga.murase@gmail.com>

completions/ssh.completion.sh

@@ -45,7 +45,11 @@ function _omb_completion_ssh {
     fi
   done
   if ((${#config_files[@]} != 0)); then
-    COMPREPLY+=($(compgen -W "$(awk '/^Host/ {for (i=2; i<=NF; i++) print $i}' "${config_files[@]}")" "${options[@]}"))
+    COMPREPLY+=($(compgen -W "$(awk '
+      sub(/^[ \t]*[Hh][Oo][Ss][Tt]([Nn][Aa][Mm][Ee])?[ \t=]+/, "") {
+        n = split($0, fields, /[ \t]+/);
+        for (i = 1; i <= n; i++) if (fields[i] != "" && !visited[fields[i]]++) print fields[i];
+      }' "${config_files[@]}")" "${options[@]}") )
   fi
 
   local -a known_hosts_files=()