Fixed bug 4277 - warnings patch

Sylvain

Patch a few warnings when using:
-Wmissing-prototypes -Wdocumentation -Wdocumentation-unknown-command

They are automatically enabled with -Wall

include/SDL_sensor.h

@@ -41,7 +41,7 @@ extern "C" {
 #endif
 
 /**
- *  \file SDL_sensor.h
+ *  \brief SDL_sensor.h
  *
  *  In order to use these functions, SDL_Init() must have been called
  *  with the ::SDL_INIT_SENSOR flag.  This causes SDL to scan the system