WHOLEMOL: fix example

(cherry picked from commit 30ff9e3c)

Conflicts:
	src/generic/WholeMolecules.cpp

src/generic/WholeMolecules.cpp

@@ -84,7 +84,7 @@ This command instructs plumed to reconstruct the chain of backbone atoms in a
 protein
 
 \verbatim
-MOLINFO REFERENCE=helix.pdb
+MOLINFO STRUCTURE=helix.pdb
 WHOLEMOLECULES STRIDE=1 RESIDUES=ALL RES_ATOMS=N,CA,CB,C,O
 \endverbatim
 (See also \ref MOLINFO)