Fix a few typos

Ref1_libsetup.txt

@@ -702,7 +702,7 @@ Libevent has released all internal library-global data structures, you can
 call:
 
 .Interface
-[Code,C]
+[code,C]
 --------
 void libevent_global_shutdown(void);
 --------

Ref3_eventloop.txt

@@ -39,7 +39,7 @@ any events are ready to trigger immediately, and run their callbacks if so.
 Ordinarily, the loop will exit as soon as it has no pending events. You can
 override this behavior by passing the EVLOOP_NO_EXIT_ON_EMPTY flag---for
 example, if you're going to be adding events from some other thread. If you
-do set EVLOO_NO_EXIT_ON_EMPTY, the loop will keep running until somebody
+do set EVLOOP_NO_EXIT_ON_EMPTY, the loop will keep running until somebody
 calls event_base_loopbreak(), or calls event_base_loopexit(), or an error
 occurs.
 

Ref6_bufferevent.txt

@@ -322,7 +322,7 @@ int bufferevent_socket_get_dns_error(struct bufferevent *bev);
 This function resolves the DNS name 'hostname', looking for addresses of type
 'family'. (Allowable family types are AF_INET, AF_INET6, and AF_UNSPEC.) If
 the name resolution fails, it invokes the event callback with an error event.
-If it succeeds, it launches a resolution attempt just as bufferevent_connect
+If it succeeds, it launches a connection attempt just as bufferevent_connect
 would.
 
 The dns_base argument is optional. If it is NULL, then Libevent blocks while

Ref6a_advanced_bufferevents.txt

@@ -99,7 +99,7 @@ struct bufferevent *bufferevent_filter_new(struct bufferevent *underlying,
 --------
 
 The bufferevent_filter_new() function creates a new filtering bufferevent,
-wrapped around and existing "underlying" bufferevent. All data received via
+wrapped around an existing "underlying" bufferevent. All data received via
 the underlying bufferevent is transformed with the "input" filter before
 arriving at the filtering bufferevent, and all data sent via the filtering
 bufferevent is transformed with an "output" filter before being sent out to

Ref7_evbuffer.txt

@@ -137,7 +137,7 @@ evbuffer_add_printf(buf, "Hello %s %d.%d.%d", "world", 2, 0, 1);
 
 The evbuffer_add() and evbuffer_add_printf() functions were introduced in
 Libevent 0.8; evbuffer_expand() was in Libevent 0.9, and
-evbuffer_add_printf() first appeared in Libevent 1.1.
+evbuffer_add_vprintf() first appeared in Libevent 1.1.
 
 Moving data from one evbuffer to another
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -728,7 +728,7 @@ for (i=0; i<n && n_to_add > 0; ++i) {
  if (len > n_to_add) /* Don't write more than n_to_add bytes. */
  len = n_to_add;
  if (generate_data(v[i].iov_base, len) < 0) {
- /* If there was a data during data generation, we can just stop
+ /* If there was a problem during data generation, we can just stop
  here; no data will be committed to the buffer. */
  return;
  }

Ref8_listener.txt

@@ -94,7 +94,7 @@ LEV_OPT_THREADSAFE::
 
 LEV_OPT_DISABLED::
  Initialize the listener to be disabled, not enabled. You can
- turn it on manually with evconnlistener_disable(). New in Libevent
+ turn it on manually with evconnlistener_enable(). New in Libevent
  2.1.1-alpha.
 
 LEV_OPT_DEFERRED_ACCEPT::

Ref9_dns.txt

@@ -468,10 +468,10 @@ options::
  How many DNS requests do we allow to be pending at once? (If
  we try to do more requests than this, the extras will stall
  until the earlier ones are answered or time out.) Defaults to
- XXX.
+ 64.
  attempts:INT;;
  How many times to we re-transmit a DNS request before giving up
- on it? Defaults to XXX.
+ on it? Defaults to 3.
  randomize-case:INT;;
  If nonzero, we randomize the case on outgoing DNS requests and
  make sure that replies have the same case as our requests. This