migrate-config: mode foo → mode "foo" (+test) (Thanks cradle)

i3-migrate-config-to-v4.pl

@@ -179,7 +179,6 @@ sub convert_command {
 
     my @unchanged_cmds = qw(
         exec
-        mode
         mark
         kill
         restart
@@ -277,6 +276,12 @@ sub convert_command {
         return;
     }
 
+    if ($command =~ /^mode/) {
+        my ($parameters) = ($command =~ /^mode (.*)/);
+        print qq|$statement $key mode "$parameters"\n|;
+        return;
+    }
+
     # the parameters of the resize command have changed
     if ($command =~ /^resize/) {
         # OLD: resize <left|right|top|bottom> [+|-]<pixels>\n")