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/stdlib/SDL_crc16.c

@@ -50,5 +50,3 @@ Uint16 SDL_crc16(Uint16 crc, const void *data, size_t len)
     }
     return crc;
 }
-
-/* vi: set ts=4 sw=4 expandtab: */

src/stdlib/SDL_crc32.c

@@ -48,5 +48,3 @@ Uint32 SDL_crc32(Uint32 crc, const void *data, size_t len)
     }
     return crc;
 }
-
-/* vi: set ts=4 sw=4 expandtab: */

src/stdlib/SDL_getenv.c

@@ -298,5 +298,3 @@ int main(int argc, char *argv[])
     return 0;
 }
 #endif /* TEST_MAIN */
-
-/* vi: set ts=4 sw=4 expandtab: */

src/stdlib/SDL_iconv.c

@@ -855,5 +855,3 @@ SDL_iconv_string(const char *tocode, const char *fromcode, const char *inbuf,
 
     return string;
 }
-
-/* vi: set ts=4 sw=4 expandtab: */

src/stdlib/SDL_malloc.c

@@ -5328,5 +5328,3 @@ void SDL_free(void *ptr)
     s_mem.free_func(ptr);
     (void)SDL_AtomicDecRef(&s_mem.num_allocations);
 }
-
-/* vi: set ts=4 sw=4 expandtab: */

src/stdlib/SDL_mslibc.c

@@ -697,5 +697,3 @@ RETZERO:
 #endif /* MSC_VER */
 
 #endif /* !HAVE_LIBC && !SDL_STATIC_LIB */
-
-/* vi: set ts=4 sw=4 expandtab: */

src/stdlib/SDL_qsort.c

@@ -560,6 +560,3 @@ SDL_bsearch(const void *key, const void *base, size_t nmemb, size_t size, int (*
     return NULL;
 #endif /* HAVE_BSEARCH */
 }
-
-/* vi: set ts=4 sw=4 expandtab: */
-

src/stdlib/SDL_stdlib.c

@@ -664,5 +664,3 @@ int SDL_isblank(int x)
     return ((x) == ' ') || ((x) == '\t');
 }
 #endif
-
-/* vi: set ts=4 sw=4 expandtab: */

src/stdlib/SDL_string.c

@@ -1956,5 +1956,3 @@ int SDL_vasprintf(char **strp, const char *fmt, va_list ap)
         }
     }
 }
-
-/* vi: set ts=4 sw=4 expandtab: */

src/stdlib/SDL_vacopy.h

@@ -32,5 +32,3 @@
 #elif defined(__GNUC__) && (__GNUC__ < 3)
 #define va_copy(dst, src) __va_copy(dst, src)
 #endif
-
-/* vi: set ts=4 sw=4 expandtab: */