Merge pull request #1747 from solt87/patch-1

Add missing definite article.

Author: ben

book/07-git-tools/sections/revision-selection.asc

@@ -147,7 +147,7 @@ For instance, to see where your `master` branch was yesterday, you can type:
 $ git show master@{yesterday}
 ----
 
-That would show you where tip of your `master` branch was yesterday.
+That would show you where the tip of your `master` branch was yesterday.
 This technique only works for data that's still in your reflog, so you can't use it to look for commits older than a few months.
 
 To see reflog information formatted like the `git log` output, you can run `git log -g`: