man: fix typo: avaialable

By slightly rewording the documentation of knet_compression_model.

Signed-off-by: Ferenc Wágner <wferi@debian.org>
Reviewed-by: Jan Friesse <jfriesse@redhat.com>

man/corosync.conf.5

@@ -402,9 +402,9 @@ The default is 238 milliseconds for two nodes cluster. Three or more nodes refer
 
 .TP
 knet_compression_model
-The (optional) type of compression used by Kronosnet. The values available depend on
-the build and also avaialable libraries. Typically zlib and lz4 will be available
-but bzip2 and others could also be allowed. The default is 'none'
+Type of compression used by Kronosnet. Supported values depend on
+the libknet build and on the installed compression libraries. Typically zlib and lz4 will be available
+but bzip2 and others could also be allowed. The default is 'none'.
 
 .TP
 knet_compression_threshold