added space in git log command example

sudarsangp · sudarsangp · commit a48db65752c9 · 2017-05-28T23:55:22.000+08:00
diff --git a/book/02-git-basics/sections/viewing-history.asc b/book/02-git-basics/sections/viewing-history.asc
@@ -250,7 +250,7 @@ For instance, if you wanted to find the last commit that added or removed a refe
 
 [source,console]
 ----
-$ git log -Sfunction_name
+$ git log -S function_name
 ----
 
 The last really useful option to pass to `git log` as a filter is a path.
