git-reflog: improve page and add branch example (#3528)

pages/common/git-reflog.md

@@ -1,12 +1,16 @@
 # git reflog
 
-> Show when the reference logs were updated in local repository.
+> Show a log of changes to local references like HEAD, branches or tags.
 > More information: <https://git-scm.com/docs/git-reflog>.
 
-- View reflog:
+- Show the reflog for HEAD:
 
 `git reflog`
 
-- View 5 latest entries in reflog:
+- Show the reflog for a given branch:
+
+`git reflog {{branch_name}}`
+
+- Show only the 5 latest entries in the reflog:
 
 `git reflog -n {{5}}`