Increase the default 3D manipulator gizmo opacity for better visibility

- Brighten gizmos when highlighted to make the difference between a
  non-highlighted and a highlighted gizmo more visible.
- Tweak the manipulator gizmo size property hint.

(cherry picked from commit 8522ac77113c3d5239ff4c6cd74ab7b92e1ee663)

editor/plugins/spatial_editor_plugin.cpp

@@ -5204,7 +5204,7 @@ void SpatialEditor::_init_indicators() {
 			gizmo_color[i] = mat;
 
 			Ref<SpatialMaterial> mat_hl = mat->duplicate();
-			mat_hl->set_albedo(Color(col.r, col.g, col.b, 1.0));
+			mat_hl->set_albedo(Color(col.r * 1.3, col.g * 1.3, col.b * 1.3, 1.0));
 			gizmo_color_hl[i] = mat_hl;
 
 			Vector3 ivec;
@@ -5302,7 +5302,7 @@ void SpatialEditor::_init_indicators() {
 				surftool->commit(move_plane_gizmo[i]);
 
 				Ref<SpatialMaterial> plane_mat_hl = plane_mat->duplicate();
-				plane_mat_hl->set_albedo(Color(col.r, col.g, col.b, 1.0));
+				plane_mat_hl->set_albedo(Color(col.r * 1.3, col.g * 1.3, col.b * 1.3, 1.0));
 				plane_gizmo_color_hl[i] = plane_mat_hl; // needed, so we can draw planes from both sides
 			}
 
@@ -5382,7 +5382,7 @@ void SpatialEditor::_init_indicators() {
 				rotate_gizmo[i]->surface_set_material(0, rotate_mat);
 
 				Ref<ShaderMaterial> rotate_mat_hl = rotate_mat->duplicate();
-				rotate_mat_hl->set_shader_param("albedo", Color(col.r, col.g, col.b, 1.0));
+				rotate_mat_hl->set_shader_param("albedo", Color(col.r * 1.3, col.g * 1.3, col.b * 1.3, 1.0));
 				rotate_gizmo_color_hl[i] = rotate_mat_hl;
 
 				if (i == 2) { // Rotation white outline
@@ -5511,7 +5511,7 @@ void SpatialEditor::_init_indicators() {
 				surftool->commit(scale_plane_gizmo[i]);
 
 				Ref<SpatialMaterial> plane_mat_hl = plane_mat->duplicate();
-				plane_mat_hl->set_albedo(Color(col.r, col.g, col.b, 1.0));
+				plane_mat_hl->set_albedo(Color(col.r * 1.3, col.g * 1.3, col.b * 1.3, 1.0));
 				plane_gizmo_color_hl[i] = plane_mat_hl; // needed, so we can draw planes from both sides
 			}
 		}
@@ -6520,8 +6520,8 @@ SpatialEditor::SpatialEditor(EditorNode *p_editor) {
 	add_to_group("_spatial_editor_group");
 
 	EDITOR_DEF("editors/3d/manipulator_gizmo_size", 80);
-	EditorSettings::get_singleton()->add_property_hint(PropertyInfo(Variant::INT, "editors/3d/manipulator_gizmo_size", PROPERTY_HINT_RANGE, "16,1024,1"));
-	EDITOR_DEF("editors/3d/manipulator_gizmo_opacity", 0.4);
+	EditorSettings::get_singleton()->add_property_hint(PropertyInfo(Variant::INT, "editors/3d/manipulator_gizmo_size", PROPERTY_HINT_RANGE, "16,160,1"));
+	EDITOR_DEF("editors/3d/manipulator_gizmo_opacity", 0.9);
 	EditorSettings::get_singleton()->add_property_hint(PropertyInfo(Variant::REAL, "editors/3d/manipulator_gizmo_opacity", PROPERTY_HINT_RANGE, "0,1,0.01"));
 	EDITOR_DEF("editors/3d/navigation/show_viewport_rotation_gizmo", true);