Better Doxyfile configure comment

Author: TartanLlama

Diff for: docs/CMakeLists.txt

@@ -12,7 +12,7 @@ set(DOXYGEN_INDEX_FILE ${DOXYGEN_OUTPUT_DIR}/xml/index.xml)
 set(DOXYFILE_IN ${CMAKE_CURRENT_SOURCE_DIR}/Doxyfile.in)
 set(DOXYFILE_OUT ${CMAKE_CURRENT_BINARY_DIR}/Doxyfile)
 
-# Replace variables inside @@ with the current values
+# Set the Doxygen input and output directories in the Doxyfile
 configure_file(${DOXYFILE_IN} ${DOXYFILE_OUT} @ONLY)
 
 # Doxygen won't create this for us