mm(1): added -t for disabling truncation; mm.1: updated docs

docs/mm.1

@@ -10,7 +10,7 @@ mm \(en middleman
 .SH SYNOPSIS
 
 mm
-.RB [ -aenu ]
+.RB [ -aetu ]
 .RB [ -i\ input ]
 .RB [ -o\ output ]
 .\"
@@ -21,19 +21,19 @@ Catenate input files and write them to the start of each output file or stream.
 .SH OPTIONS
 
 .IP \fB-a\fP
-Opens subsequent outputs for appending rather than updating.
+Opens outputs for appending rather than updating.
 .IP \fB-e\fP
 Use the standard error as an output.
+.IP \fB-t\fP
+Causes outputs to be overwritten instead of being truncated.
+.IP \fB-u\fP
+Ensures neither input or output will be buffered.
 .IP \fB-i\fP\ \fIinput\fP
 Opens a path as an input. If one or more of the input files is \(lq-\(rq or if
 no inputs are specified, the standard input shall be used.
 .IP \fB-o\fP\ \fIoutput\fP
 Opens a path as an output. If one or more of the output files is \(lq-\(rq or if
 no outputs are specified, the standard output shall be used.
-.IP \fB-u\fP
-Ensures neither input or output will be buffered.
-.IP \fB-n\fP
-Causes SIGINT signals to be ignored.
 .\"
 .SH DIAGNOSTICS
 
@@ -45,10 +45,6 @@ exits with the appropriate
 .BR sysexits.h (3)
 status.
 .\"
-.SH CAVEATS
-
-Existing files are not truncated on ouput and are instead overwritten.
-.\"
 .SH RATIONALE
 
 The