Update Debugging.rst

docs/source_docs/Debugging.rst

@@ -10,7 +10,7 @@ Debugging is an art.  Everyone has their own favorite method.  Here we
 offer a few tips we have found to be useful.
 
 Compiling in debug mode (e.g., :cpp:`make DEBUG=TRUE` for gmake users;
-:cpp:`cmake -DDEBUG` for cmake users) and running with
+:cpp:`cmake -DCMAKE_BUILD_TYPE=Debug` for cmake users) and running with
 :cpp:`amrex.fpe_trap_invalid=1` in the inputs file can be helpful.
 In debug mode, many compiler debugging flags are turned on and all
 :cpp:`MultiFab` s are initialized to signaling NaNs.  The