Fix grammar on how git svn fetches tags

The wording "rather than treating them remote branches." is missing a preposition "as".

Author: ablomm

book/09-git-and-other-scms/sections/client-svn.asc

@@ -158,7 +158,7 @@ c3dcbe8488c6240392e8a5d7553bbffcb0f94ef0 refs/remotes/origin/master
 6dcb09b5b57875f334f61aebed695e2e4193db5e refs/tags/v1.0.0
 ----
 
-Git fetches the tags directly into `refs/tags`, rather than treating them remote branches.
+Git fetches the tags directly into `refs/tags`, rather than treating them as remote branches.
 
 ===== Committing Back to Subversion