Fixed header documentation errors

include/SDL_joystick.h

@@ -275,7 +275,7 @@ extern DECLSPEC SDL_Joystick *SDLCALL SDL_JoystickOpen(int device_index);
 /**
  * Get the SDL_Joystick associated with an instance id.
  *
- * \param joyid the instance id to get the SDL_Joystick for
+ * \param instance_id the instance id to get the SDL_Joystick for
  * \returns an SDL_Joystick on success or NULL on failure; call SDL_GetError()
  *          for more information.
  *

include/SDL_video.h

@@ -438,7 +438,7 @@ extern DECLSPEC int SDLCALL SDL_GetDisplayDPI(int displayIndex, float * ddpi, fl
 /**
  * Get the orientation of a display.
  *
- * \params displayIndex the index of the display to query
+ * \param displayIndex the index of the display to query
  * \returns The SDL_DisplayOrientation enum value of the display, or
  *          `SDL_ORIENTATION_UNKNOWN` if it isn't available.
  *
@@ -1314,7 +1314,7 @@ extern DECLSPEC int SDLCALL SDL_SetWindowOpacity(SDL_Window * window, float opac
  * This function also returns -1 if an invalid window was provided.
  *
  * \param window the window to get the current opacity value from
- * \param opacity the float filled in (0.0f - transparent, 1.0f - opaque)
+ * \param out_opacity the float filled in (0.0f - transparent, 1.0f - opaque)
  * \returns 0 on success or a negative error code on failure; call
  *          SDL_GetError() for more information.
  *

include/SDL_vulkan.h

@@ -149,7 +149,7 @@ extern DECLSPEC void SDLCALL SDL_Vulkan_UnloadLibrary(void);
  *               should be retrieved (will be deprecated in a future release)
  * \param pCount A pointer to an unsigned int corresponding to the
  *               number of extensions to be returned
- * \param names NULL or a pointer to an array to be filled with required
+ * \param pNames NULL or a pointer to an array to be filled with required
  *              Vulkan instance extensions
  * \returns SDL_TRUE on success, SDL_FALSE on error.
  *