docs/sphinx: Fix various typos

(This modifies UI, libobs, deps/obs-scripting, various cmake files)

Found using:
`codespell -q 3 -S *.ini,./UI/data/locale,./deps/w32-pthreads -L aci,dur,iff,mut,numer,uint`

UI/audio-encoders.cpp

@@ -175,7 +175,7 @@ static void PopulateBitrateMap()
 			if (aac_ != GetCodec(encoder.c_str()))
 				continue;
 
-			// disable mf_aac if audio ouput is not stereo nor mono
+			// disable mf_aac if audio output is not stereo nor mono
 			if ((output_channels >= 3) && (encoder == "mf_aac"))
 				continue;
 

UI/data/themes/Acri.qss

@@ -957,7 +957,7 @@ LockedCheckBox::indicator:unchecked:hover {
     image: url(:res/images/unlocked.svg);
 }
 
-/* Visibilty CheckBox */
+/* Visibility CheckBox */
 
 VisibilityCheckBox {
     outline: none;

UI/data/themes/Dark.qss

@@ -715,7 +715,7 @@ LockedCheckBox::indicator:unchecked {
     image: url(:res/images/unlocked.svg);
 }
 
-/* Visibilty CheckBox */
+/* Visibility CheckBox */
 
 VisibilityCheckBox {
     outline: none;

UI/data/themes/Rachni.qss

@@ -1293,7 +1293,7 @@ LockedCheckBox::indicator:unchecked:hover {
     image: url(:res/images/unlocked.svg);
 }
 
-/* Visibilty CheckBox */
+/* Visibility CheckBox */
 
 VisibilityCheckBox {
     outline: none;

UI/data/themes/System.qss

@@ -186,7 +186,7 @@ LockedCheckBox::indicator:unchecked {
     image: url(:res/images/unlocked.svg);
 }
 
-/* Visibilty CheckBox */
+/* Visibility CheckBox */
 
 VisibilityCheckBox {
     outline: none;

UI/volume-control.cpp

@@ -488,7 +488,7 @@ void VolumeMeter::setPeakMeterType(enum obs_peak_meter_type peakMeterType)
 		// processing required by lossy audio compression.
 		//
 		// The alignment level was not specified, but I've adjusted
-		// it compared to a sample-peak meter. Incidently Youtube
+		// it compared to a sample-peak meter. Incidentally Youtube
 		// uses this new Alignment Level as the maximum integrated
 		// loudness of a video.
 		//

UI/window-projector.cpp

@@ -591,7 +591,7 @@ void OBSProjector::OBSRenderMultiview(void *data, uint32_t cx, uint32_t cy)
 		gs_matrix_pop();
 	}
 
-	// Region for future usage with aditional info.
+	// Region for future usage with additional info.
 	if (multiviewLayout == MultiviewLayout::HORIZONTAL_TOP_24_SCENES) {
 		// Just paint the background for now
 		paintAreaWithColor(window->thickness, window->thickness,