LibGUI+Everywhere: Use fallible Window::set_main_widget() everywhere :^)

Rip that bandaid off!

This does the following, in one big, awkward jump:
- Replace all uses of `set_main_widget<Foo>()` with the `try` version.
- Remove `set_main_widget<Foo>()`.
- Rename the `try` version to just be `set_main_widget` because it's now
  the only one.

The majority of places that call `set_main_widget<Foo>()` are inside
constructors, so this unfortunately gives us a big batch of new
`release_value_but_fixme_should_propagate_errors()` calls.

1 files changed, 2 insertions, 2 deletions

diff --git a/Userland/Applets/Audio/main.cpp b/Userland/Applets/Audio/main.cpp
index a217edde68..2ec64907eb 100644
--- a/Userland/Applets/Audio/main.cpp
+++ b/Userland/Applets/Audio/main.cpp
@@ -80,7 +80,7 @@ private:
         m_slider_window = add<GUI::Window>(window());
         m_slider_window->set_window_type(GUI::WindowType::Popup);
 
-        m_root_container = TRY(m_slider_window->try_set_main_widget<GUI::Frame>());
+        m_root_container = TRY(m_slider_window->set_main_widget<GUI::Frame>());
         m_root_container->set_fill_with_background_color(true);
         m_root_container->set_layout<GUI::VerticalBoxLayout>();
         m_root_container->layout()->set_margins({ 4 });
@@ -245,7 +245,7 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
     window->set_title("Audio");
     window->set_window_type(GUI::WindowType::Applet);
 
-    auto audio_widget = TRY(window->try_set_main_widget<AudioWidget>());
+    auto audio_widget = TRY(window->set_main_widget<AudioWidget>());
     window->show();
 
     // This positioning code depends on the window actually existing.