Fix copy-and-paste typo in doc

[update-doc]

Author: giacomofiorin

doc/colvars-refman-main.tex

@@ -3765,7 +3765,7 @@
 \item %
   \labelkey{colvar|mapTotal|atomWeights}
   \keydef
-    {atoms}{%
+    {atomWeights}{%
     \texttt{mapTotal}}{%
     Weights to assign to each atom}{%
     list of space-separated decimals}{%