Follow OpenGL naming in Context::Flag enum.

As usual, the old Context::Flag::Robustness is marked deprecated and
will be removed in future release.

src/Magnum/Context.h

@@ -119,14 +119,22 @@ class MAGNUM_EXPORT Context {
 
             #ifndef MAGNUM_TARGET_GLES
             /**
-             * Context with robust buffer access
+             * Context with robust access
              * @requires_extension %Extension @extension{ARB,robustness}
              * @requires_es_extension %Extension @es_extension{EXT,robustness}
              * @todo In ES available under glGetIntegerv(CONTEXT_ROBUST_ACCESS_EXT),
              *      how to make it compatible?
              */
+            RobustAccess = GL_CONTEXT_FLAG_ROBUST_ACCESS_BIT_ARB,
+
+            #ifdef MAGNUM_BUILD_DEPRECATED
+            /**
+             * @copybrief Context::Flag::RobustAccess
+             * @deprecated Use @ref Magnum::Context::Flag::RobustAccess "Context::Flag::RobustAccess" instead.
+             */
             Robustness = GL_CONTEXT_FLAG_ROBUST_ACCESS_BIT_ARB
             #endif
+            #endif
         };
 
         /**