[*] basic in-house cpp linting (#4039)

- add `#pragma once` to remainder files
- "correcter" defines (ANDROID), see https://groups.google.com/g/android-ndk/c/cf9_f1SLXls
- extra miscelly fixups

Signed-off-by: lizzie <lizzie@eden-emu.dev>

Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/4039
Reviewed-by: MaranBr <maranbr@eden-emu.dev>
Reviewed-by: crueter <crueter@eden-emu.dev>

src/qt_common/util/content.h

@@ -1,8 +1,7 @@
 // SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
 // SPDX-License-Identifier: GPL-3.0-or-later
 
-#ifndef QT_CONTENT_UTIL_H
-#define QT_CONTENT_UTIL_H
+#pragma once
 
 #include <QObject>
 #include "common/common_types.h"
@@ -63,4 +62,3 @@ void configureFilesystemProvider(const std::string& filepath);
 // Profiles //
 void FixProfiles();
 } // namespace QtCommon::Content
-#endif // QT_CONTENT_UTIL_H