vcs.4: Convert inline formatting (\fX...\fP) to dot-directive formatting

Plus other formatting fixes

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

man4/vcs.4

@@ -30,28 +30,40 @@
 .SH NAME
 vcs, vcsa \- virtual console memory
 .SH DESCRIPTION
-\fI/dev/vcs0\fP is a character device with major number 7 and minor number
+.I /dev/vcs0
+is a character device with major number 7 and minor number
 0, usually of mode 0644 and owner root.tty.
 It refers to the memory of the currently
 displayed virtual console terminal.
 .LP
-\fI/dev/vcs[1\-63]\fP are character devices for virtual console
+.I /dev/vcs[1\-63]
+are character devices for virtual console
 terminals, they have major number 7 and minor number 1 to 63, usually
 mode 0644 and owner root.tty.
-\fI/dev/vcsa[0\-63]\fP are the same, but
+.IR /dev/vcsa[0\-63]
+are the same, but
 using
 .IR "unsigned short" s
 (in host byte order) that include attributes,
 and prefixed with four bytes giving the screen
-dimensions and cursor position: \fIlines\fP, \fIcolumns\fP, \fIx\fP, \fIy\fP.
-(\fIx\fP = \fIy\fP = 0 at the top left corner of the screen.)
+dimensions and cursor position:
+.IR lines ,
+.IR columns ,
+.IR x ,
+.IR y .
+.RI ( x
+=
+.I y
+= 0 at the top left corner of the screen.)
 
 When a 512-character font is loaded,
 the 9th bit position can be fetched by applying the
 .BR ioctl (2)
-\fBVT_GETHIFONTMASK\fP operation
+.B VT_GETHIFONTMASK
+operation
 (available in Linux kernels 2.6.18 and above)
-on \fI/dev/tty[1\-63]\fP;
+on 
+.IR /dev/tty[1\-63] ;
 the value is returned in the
 .I "unsigned short"
 pointed to by the third
@@ -88,13 +100,23 @@ requests are supported.
 Introduced with version 1.1.92 of the Linux kernel.
 .SH EXAMPLE
 You may do a screendump on vt3 by switching to vt1 and typing
-\fIcat /dev/vcs3 >foo\fP.
+
+    cat /dev/vcs3 >foo
+
 Note that the output does not contain
 newline characters, so some processing may be required, like
-in \fIfold \-w 81 /dev/vcs3 | lpr\fP or (horrors)
-\fIsetterm \-dump 3 \-file /proc/self/fd/1\fP.
+in
+
+    old \-w 81 /dev/vcs3 | lpr
+
+or (horrors)
+
+    xetterm \-dump 3 \-file /proc/self/fd/1
+
 .LP
-The \fI/dev/vcsa0\fP device is used for Braille support.
+The
+.I /dev/vcsa0
+device is used for Braille support.
 
 This program displays the character and screen attributes under the
 cursor of the second virtual console, then changes the background color