Remove irr namespace (#16309)

irr/include/IContextManager.h

@@ -8,8 +8,6 @@
 #include "SIrrCreationParameters.h"
 #include <string>
 
-namespace irr
-{
 namespace video
 {
 // For system specific window contexts (used for OpenGL)
@@ -43,7 +41,7 @@ public:
 	/** This is mostly used internally by IVideoDriver::beginScene().
 		But if you want to switch threads which access your OpenGL driver you will have to
 		call this function as follows:
-		Old thread gives up context with: activateContext(irr::video::SExposedVideoData());
+		Old thread gives up context with: activateContext(video::SExposedVideoData());
 		New thread takes over context with: activateContext(videoDriver->getExposedVideoData());
 		Note that only 1 thread at a time may access an OpenGL context.	*/
 	virtual bool activateContext(const SExposedVideoData &videoData, bool restorePrimaryOnZero = false) = 0;
@@ -56,4 +54,3 @@ public:
 };
 
 } // end namespace video
-} // end namespace irr