tcs(1): document new Runeerror, correct bad-UTF-near-EOF bug.
 [rsc] --rw-rw-r-- M 1061556 glenda sys 2654 Mar 23 11:26 sys/man/1/tcs
	/n/sourcesdump/2006/0323/plan9/sys/man/1/tcs:48,59 - 
	/n/sourcesdump/2006/0324/plan9/sys/man/1/tcs:48,58
	  .B -c
	  option forces the output to contain only correctly converted characters;
	  otherwise,
	- .B 0x80
	+ .B Runeerror
	+ (0xFFFD)
	  characters will be substituted for
	  .SM UTF
	- encoding errors and
	- .B 0xFFFD
	- characters will substituted for unknown characters.
	+ encoding errors and unknown characters.
	  .PP
	  The
	  .B -v
 [rsc] --rw-rw-r-- M 1061556 glenda sys 7907 Mar 23 11:26 sys/src/cmd/tcs/utf.c
	[diffs elided - too long]
	[diff -c /n/sourcesdump/2006/0323/plan9/sys/src/cmd/tcs/utf.c /n/sourcesdump/2006/0324/plan9/sys/src/cmd/tcs/utf.c]