Revert "Fix #1736: on GNU/Linux, a hotkey can trigger multiple commands"

This reverts commit c42401a8de.

As @CelticMinstrel pointed out, that commit made it impossible to input characters which require
AltGr to type (e.g. @, € and $ in Finnish keyboard).

Reopens #1736.

src/events.cpp

@@ -488,15 +488,6 @@ void run_event_loop()
 		last_resize_event_used = true;
 	}
 
-	if(SDL_GetModState() & KMOD_ALT) {
-		// Remove text input events, to match the behavior on Windows
-		// See https://github.com/wesnoth/wesnoth/issues/1736
-		events.erase(
-			std::remove_if(events.begin(), events.end(), [](const SDL_Event& e) { return e.type == SDL_TEXTINPUT; }),
-			events.end()
-		);
-	}
-
 	ev_end = events.end();
 
 	for(ev_it = events.begin(); ev_it != ev_end; ++ev_it) {