Fix searching windows by ahk_class

sometimes, when `class` and `class_name` differ, the value of `WinGetClass` and the used value for searching `ahk_class` were different. Now only the non-name `class` value is handled.

Fixes #60

src/cmd/x11/window/win-get-class.cr

@@ -7,6 +7,7 @@ class Cmd::X11::Window::WinGetClass < Cmd::Base
 		match_conditions = args[1..]? || [] of ::String
 		out_var = args[0]
 		Util.match(thread, match_conditions, empty_is_last_found: true, a_is_active: true) do |win|
+			# We seem to actually get class here, not class_name
 			thread.runner.set_user_var(out_var, win.class_name || "")
 			return
 		end

src/cmd/x11/window/win-util.cr

@@ -34,7 +34,7 @@ class Cmd::X11::Window::Util
 					end
 					if title.starts_with?("ahk_class ")
 						# TODO: these/name etc should all be case sensitive. Maybe double filter below? How performant is querying for .name etc?
-						window_class_name title[10..] # TODO: is this regex? how to make partial matches like ahk?
+						window_class title[10..] # TODO: is this regex? how to make partial matches like ahk?
 					else
 						title = ".*" if title.empty?
 						window_name title # todo same as above / seems to be partial match but only at *start* of string