include: Add \since to all documentation that was missing it.

include/SDL3/SDL_sensor.h

@@ -57,6 +57,8 @@ typedef struct SDL_Sensor SDL_Sensor;
  *
  * The ID value starts at 1 and increments from there. The value 0 is an
  * invalid ID.
+ *
+ * \since This datatype is available since SDL 3.0.0.
  */
 typedef Uint32 SDL_SensorID;
 
@@ -99,6 +101,8 @@ typedef enum
  *
  * The axis data is not changed when the device is rotated.
  *
+ * \since This macro is available since SDL 3.0.0.
+ *
  * \sa SDL_GetCurrentDisplayOrientation
  */
 #define SDL_STANDARD_GRAVITY    9.80665f