doc: move notes to manual and clarify the synopsis

Since the README is not intended to be installed to the system it makes
sense to provide the NOTES section in the manual itself which is.

This also expands the SYNOPSIS section to indicate that the usage of sx
should work as a typical chain command.

README

@@ -34,12 +34,6 @@ INTRODUCTION
   For a rationale on why this exists, the author invites the reader to
   look over the source code for both xinit and startx.
 
-NOTES
-
-  Since the addition of Xorg.wrap it may be necessary to set allowed_users
-  to anybody in /etc/X11/Xwrapper.config as sx attempts to start clients
-  from within a subshell and is thusly not considered a console user.
-
 REQUIRES
 
   * Xorg

sx.1

@@ -1,9 +1,9 @@
-.TH SX 1 2017-12-09 Linux
+.TH SX 1 "25 August 2018"
 .SH NAME
 sx \- start an xorg server
 .SH SYNOPSIS
 .B sx
-.RI [ client ]
+.RI [ "command " [ "arguments " ...]]
 .SH DESCRIPTION
 .B sx
 can be used to replace both
@@ -15,8 +15,11 @@ for starting an Xorg server.  By default
 will attempt execute
 .I sxrc
 unless a
-.I client
-argument is provided.
+.I command
+argument is provided.  The
+.I command
+may consistent of one or more
+.IR arguments .
 .SH ENVIRONMENT
 .TP
 .B XAUTHORITY
@@ -45,7 +48,7 @@ will be used if not set.
 .SH FILES
 .TP
 .B XDG_CONFIG_HOME/sx/sxrc
-The default client started by
+The default command started by
 .BR sx .
 This file must be executable.
 .TP
@@ -54,6 +57,19 @@ The default authority used by
 .B sx
 if an alternative file is not provided with
 .BR XAUTHORITY .
+.SH NOTES
+Since the addition of
+.BR Xorg.wrap (1)
+it may be necessary to set
+.I allowed_users
+to
+.I anybody
+in
+.BR \%/etc/X11/Xwrapper.config .
+This is due to
+.B sx
+attempting to run commands from within a subshell and is thusly not considered
+a console user.
 .SH SOURCE
 .UR https://github.com/Earnestly/sx
 .UE