DOC: fix name for "option independant-streams"

The correct spelling is "independent", not "independant". This patch
fixes the doc and the configuration parser to accept the correct form.
The config parser still allows the old naming for backwards compatibility.
diff --git a/include/types/proxy.h b/include/types/proxy.h
index 53dd96d..c93edd2 100644
--- a/include/types/proxy.h
+++ b/include/types/proxy.h
@@ -119,7 +119,7 @@
 #define PR_O2_RDPC_PRST	0x00000200      /* Actvate rdp cookie analyser */
 #define PR_O2_CLFLOG	0x00000400      /* log into clf format */
 #define PR_O2_LOGHCHKS	0x00000800	/* log health checks */
-#define PR_O2_INDEPSTR	0x00001000	/* independant streams, don't update rex on write */
+#define PR_O2_INDEPSTR	0x00001000	/* independent streams, don't update rex on write */
 #define PR_O2_SOCKSTAT	0x00002000	/* collect & provide separate statistics for sockets */
 
 /* appsession */
diff --git a/include/types/stream_interface.h b/include/types/stream_interface.h
index b11b398..311cf0e 100644
--- a/include/types/stream_interface.h
+++ b/include/types/stream_interface.h
@@ -28,7 +28,7 @@
 #include <types/buffers.h>
 #include <common/config.h>
 
-/* A stream interface must have its own errors independantly of the buffer's,
+/* A stream interface must have its own errors independently of the buffer's,
  * so that applications can rely on what the buffer reports while the stream
  * interface is performing some retries (eg: connection error). Some states are
  * transient and do not last beyond process_session().
@@ -70,7 +70,7 @@
 	SI_FL_WAIT_DATA  = 0x0008,  /* waiting for more data to send */
 	SI_FL_CAP_SPLTCP = 0x0010,  /* splicing possible from/to TCP */
 	SI_FL_DONT_WAKE  = 0x0020,  /* resync in progress, don't wake up */
-	SI_FL_INDEP_STR  = 0x0040,  /* independant streams = don't update rex on write */
+	SI_FL_INDEP_STR  = 0x0040,  /* independent streams = don't update rex on write */
 	SI_FL_NOLINGER   = 0x0080,  /* may close without lingering. One-shot. */
 	SI_FL_NOHALF     = 0x0100,  /* no half close, close both sides at once */
 	SI_FL_SRC_ADDR   = 0x1000,  /* get the source ip/port with getsockname */