Changed commands about tags in understanding-git

FormaContinue_MeteoNov2017/Slides/understanding-git.tex

@@ -519,14 +519,14 @@ $ git rev-parse refs/heads/master
   \begin{itemize}
   \item Create a local branch and check it out:\\
     \texttt{git checkout -b \textit{branch-name}}
-  \item Switch to a branch:\\
-    \texttt{git checkout \textit{branch-name}}
   \item List local branches:\\
     \texttt{git branch}
   \item List all branches (including remote-tracking):\\
     \texttt{git branch -a}
   \item Create a tag:\\
     \texttt{git tag \textit{tag-name}}
+  \item Switch to a branch, a tag, or a commit:\\
+    \texttt{git checkout \textit{branch-name/tag-name/commit}}
   \end{itemize}
 \end{frame}