Fix issue progit#533: Not all local branches can merge with its remote-tracking branch by a single git pull command at once

The merge feature of git pull only works on current branch.

Author: YueLinHo

book/02-git-basics/sections/remotes.asc

@@ -189,7 +189,7 @@ $ git remote show origin
 ----
 
 This command shows which branch is automatically pushed to when you run `git push` while on certain branches.
-It also shows you which remote branches on the server you don't yet have, which remote branches you have that have been removed from the server, and multiple branches that are automatically merged when you run `git pull`.
+It also shows you which remote branches on the server you don't yet have, which remote branches you have that have been removed from the server, and multiple local branches that are able to merge automatically with their remote-tracking branch when you run `git pull`.
 
 ==== Removing and Renaming Remotes