HDRenderPipeline: Edit description of normal map for BC5

Assets/ScriptableRenderPipeline/HDRenderPipeline/Material/Lit/Editor/LitUI.cs

             public static GUIContent maskMapSText = new GUIContent("Mask Map - M(R), AO(G), S(A)", "Mask map");
 
             public static GUIContent normalMapSpaceText = new GUIContent("Normal/Tangent Map space", "");
+            public static GUIContent normalMapText = new GUIContent("Normal Map", "Normal Map (BC7/BC5/DXT5(nm))");
             public static GUIContent specularOcclusionMapText = new GUIContent("Specular Occlusion Map (RGBA)", "Specular Occlusion Map");
             public static GUIContent horizonFadeText = new GUIContent("Horizon Fade (Spec occlusion)", "horizon fade is use to control specular occlusion");