[bugfix,documentation] Fix spelling
(cherry picked from commit 87bf8f3eb8f36bc4060efb9f9684726e0fe5ed9c)

Signed-off-by: Markus Blatt <markus@dr-blatt.de>
[cmake,bugfix] Adds missing @ to variable on config.h.cmake
(cherry picked from commit 7fbd70bad9ebd3bfa4a22019c21db793db31abe7)

Signed-off-by: Markus Blatt <markus@dr-blatt.de>