(fix) Restore manual aiming across z-levels

Fully remove never-set variable and checks for it that prevented
manual z-level aiming. This was previously set based on the z-levels
option, but that option was removed in #9543 and the variable remained
still checked (and thus could never be true). This seemed unintentional
and broke manual aiming across z-levels.

Author: tehkab

src/ranged.cpp

@@ -481,8 +481,6 @@ class target_ui
         // List of visible hostile targets
         std::vector<Creature *> targets;
 
-        // 'true' if map has z levels and 3D fov is on
-        bool allow_zlevel_shift = false;
         // Snap camera to cursor. Can be permanently toggled in settings
         // or temporarily in this window
         bool snap_to_target = false;
@@ -3235,10 +3233,8 @@ void target_ui::init_window_and_input()
     ctxt.register_action( "zoom_out" );
     ctxt.register_action( "zoom_in" );
     ctxt.register_action( "TOGGLE_MOVE_CURSOR_VIEW" );
-    if( allow_zlevel_shift ) {
-        ctxt.register_action( "LEVEL_UP" );
-        ctxt.register_action( "LEVEL_DOWN" );
-    }
+    ctxt.register_action( "LEVEL_UP" );
+    ctxt.register_action( "LEVEL_DOWN" );
     if( mode == TargetMode::Fire || mode == TargetMode::TurretManual || ( mode == TargetMode::Shape &&
             relevant->is_gun() ) ) {
         ctxt.register_action( "SWITCH_MODE" );
@@ -4262,9 +4258,7 @@ void target_ui::panel_cursor_info( int &text_y )
 
     std::vector<std::string> labels;
     labels.push_back( label_range );
-    if( allow_zlevel_shift ) {
-        labels.push_back( string_format( _( "Elevation: %d" ), dst.z() - src.z() ) );
-    }
+    labels.push_back( string_format( _( "Elevation: %d" ), dst.z() - src.z() ) );
     labels.push_back( string_format( _( "Targets: %d" ), targets.size() ) );
 
     nc_color col = c_light_gray;