Fixed typo in internal joystick documentation comments.

src/joystick/android/SDL_sysjoystick.c

@@ -495,7 +495,7 @@ SDL_SYS_JoystickOpen(SDL_Joystick * joystick, int device_index)
     return (0);
 }
 
-/* Function to determine is this joystick is attached to the system right now */
+/* Function to determine if this joystick is attached to the system right now */
 SDL_bool SDL_SYS_JoystickAttached(SDL_Joystick *joystick)
 {
     return joystick->hwdata != NULL;

src/joystick/bsd/SDL_sysjoystick.c

@@ -421,7 +421,7 @@ SDL_SYS_JoystickOpen(SDL_Joystick * joy, int device_index)
     return (-1);
 }
 
-/* Function to determine is this joystick is attached to the system right now */
+/* Function to determine if this joystick is attached to the system right now */
 SDL_bool SDL_SYS_JoystickAttached(SDL_Joystick *joystick)
 {
     return SDL_TRUE;

src/joystick/dummy/SDL_sysjoystick.c

@@ -71,7 +71,7 @@ SDL_SYS_JoystickOpen(SDL_Joystick * joystick, int device_index)
     return SDL_SetError("Logic error: No joysticks available");
 }
 
-/* Function to determine is this joystick is attached to the system right now */
+/* Function to determine if this joystick is attached to the system right now */
 SDL_bool SDL_SYS_JoystickAttached(SDL_Joystick *joystick)
 {
     return SDL_TRUE;

src/joystick/emscripten/SDL_sysjoystick.c

@@ -323,7 +323,7 @@ SDL_SYS_JoystickOpen(SDL_Joystick * joystick, int device_index)
     return (0);
 }
 
-/* Function to determine is this joystick is attached to the system right now */
+/* Function to determine if this joystick is attached to the system right now */
 SDL_bool SDL_SYS_JoystickAttached(SDL_Joystick *joystick)
 {
     return joystick->hwdata != NULL;

src/joystick/haiku/SDL_haikujoystick.cc

@@ -152,7 +152,7 @@ extern "C"
         return (0);
     }
 
-/* Function to determine is this joystick is attached to the system right now */
+/* Function to determine if this joystick is attached to the system right now */
     SDL_bool SDL_SYS_JoystickAttached(SDL_Joystick *joystick)
     {
         return SDL_TRUE;

src/joystick/iphoneos/SDL_sysjoystick.m

@@ -102,7 +102,7 @@ SDL_SYS_JoystickOpen(SDL_Joystick * joystick, int device_index)
     return 0;
 }
 
-/* Function to determine is this joystick is attached to the system right now */
+/* Function to determine if this joystick is attached to the system right now */
 SDL_bool SDL_SYS_JoystickAttached(SDL_Joystick *joystick)
 {
     return SDL_TRUE;

src/joystick/linux/SDL_sysjoystick.c

@@ -621,7 +621,7 @@ SDL_SYS_JoystickOpen(SDL_Joystick * joystick, int device_index)
     return (0);
 }
 
-/* Function to determine is this joystick is attached to the system right now */
+/* Function to determine if this joystick is attached to the system right now */
 SDL_bool SDL_SYS_JoystickAttached(SDL_Joystick *joystick)
 {
     return joystick->hwdata->item != NULL;

src/joystick/psp/SDL_sysjoystick.c

@@ -177,7 +177,7 @@ int SDL_SYS_JoystickOpen(SDL_Joystick *joystick, int device_index)
     return 0;
 }
 
-/* Function to determine is this joystick is attached to the system right now */
+/* Function to determine if this joystick is attached to the system right now */
 SDL_bool SDL_SYS_JoystickAttached(SDL_Joystick *joystick)
 {
     return SDL_TRUE;

src/joystick/windows/SDL_mmjoystick.c

@@ -271,7 +271,7 @@ SDL_SYS_JoystickOpen(SDL_Joystick * joystick, int device_index)
     return (0);
 }
 
-/* Function to determine is this joystick is attached to the system right now */
+/* Function to determine if this joystick is attached to the system right now */
 SDL_bool SDL_SYS_JoystickAttached(SDL_Joystick *joystick)
 {
     return SDL_TRUE;