Fixed some typos, courtesy of codespell

src/libfast/fast_dispatcher.h

@@ -24,7 +24,7 @@
  *
  * The application has a global context and a session context. The global
  * context is accessed from all sessions simultaneously and therefore
- * needs to be threadsave. Often a database wrapper is the global context.
+ * needs to be threadsafe. Often a database wrapper is the global context.
  * The session context is instantiated per session. Sessions are managed
  * automatically through session cookies. The session context is kept alive
  * until the session times out. It must implement the context_t interface and

src/libfast/fast_request.c

@@ -75,7 +75,7 @@ struct private_fast_request_t {
 };
 
 /**
- * ClearSilver cgiwrap is not threadsave, so we use a private
+ * ClearSilver cgiwrap is not threadsafe, so we use a private
  * context for each thread.
  */
 static thread_value_t *thread_this;