tweak punctuation

Author: tbrowder

doc/Language/faq.pod6

@@ -960,7 +960,7 @@ for an overview of implemented features.
 =head2 Is Perl 6 fast enough for me?
 
 That depends on what you are doing. Rakudo has been developed with the
-philosophy of "make it work right then make it work fast". It's fast for some
+philosophy of "make it work right then make it work fast." It's fast for some
 things already but needs work for others. Since Perl 6 provides lots of clues
 to the JIT that other dynamic languages don't, we think we'll have a lot of
 headroom for performance improvements.