Removed the vi format comments from the source

Vim users can use the [editorconfig plugin](https://github.com/editorconfig/editorconfig-vim) to automatically set tab spacing for the SDL coding style.

Fixes https://github.com/libsdl-org/SDL/issues/6903

src/thread/windows/SDL_syscond_cv.c

@@ -267,5 +267,3 @@ int SDL_CondWaitTimeoutNS(SDL_cond *cond, SDL_mutex *mutex, Sint64 timeoutNS)
 {
     return SDL_cond_impl_active.WaitTimeoutNS(cond, mutex, timeoutNS);
 }
-
-/* vi: set ts=4 sw=4 expandtab: */

src/thread/windows/SDL_sysmutex.c

@@ -284,5 +284,3 @@ int SDL_UnlockMutex(SDL_mutex *mutex)
 }
 
 #endif /* SDL_THREAD_WINDOWS */
-
-/* vi: set ts=4 sw=4 expandtab: */

src/thread/windows/SDL_sysmutex_c.h

@@ -71,5 +71,3 @@ typedef struct SDL_mutex_cs
 {
     CRITICAL_SECTION cs;
 } SDL_mutex_cs;
-
-/* vi: set ts=4 sw=4 expandtab: */

src/thread/windows/SDL_syssem.c

@@ -395,5 +395,3 @@ int SDL_SemPost(SDL_sem *sem)
 }
 
 #endif /* SDL_THREAD_WINDOWS */
-
-/* vi: set ts=4 sw=4 expandtab: */

src/thread/windows/SDL_systhread.c

@@ -211,5 +211,3 @@ void SDL_SYS_DetachThread(SDL_Thread *thread)
 }
 
 #endif /* SDL_THREAD_WINDOWS */
-
-/* vi: set ts=4 sw=4 expandtab: */

src/thread/windows/SDL_systhread_c.h

@@ -28,5 +28,3 @@
 typedef HANDLE SYS_ThreadHandle;
 
 #endif /* SDL_systhread_c_h_ */
-
-/* vi: set ts=4 sw=4 expandtab: */

src/thread/windows/SDL_systls.c

@@ -78,5 +78,3 @@ int SDL_SYS_SetTLSData(SDL_TLSData *data)
 }
 
 #endif /* SDL_THREAD_WINDOWS */
-
-/* vi: set ts=4 sw=4 expandtab: */