Fix render engine info region when overlap and header on bottom

Note there is some talk about changing the position of this (which would be strange in the image editor by the way,
since there we use the bottom for the result of the current pixel when dragging the mouse).

However first I wanted to fix this regardless.

source/blender/editors/screen/area.c

@@ -2258,7 +2258,7 @@ void ED_region_info_draw_multiline(ARegion *ar, const char *text_array[], float
 		}
 	}
 
-	rect.ymin = BLI_rcti_size_y(&rect) - header_height * num_lines;
+	rect.ymin = rect.ymax - header_height * num_lines;
 
 	/* setup scissor */
 	glGetIntegerv(GL_SCISSOR_BOX, scissor);