Fix quotation mark in ruby example.

jeremyschlatter · jeremyschlatter · commit 3709e8f92bbe · 2015-05-15T16:08:15.000-07:00
diff --git a/src/doc/trpl/rust-inside-other-languages.md b/src/doc/trpl/rust-inside-other-languages.md
@@ -217,7 +217,7 @@ end
 
 Hello.process
 
-puts "done!”
+puts "done!"
 ```
 
 Before we can run this, we need to install the `ffi` gem:
