doc: Clean up roff source in manpage

* The header's comments were written incorrectly. A comment line in Roff
  starts with a .\" sequence, whereas .\ is attempting to call a command
  whose name starts with a space. Because Roff interpreters will discard
  unrecognised control lines, the malformed "comments" were just noops.

* Repeating font macros have been used to format the synopsis instead of
  escape sequences (\fB…\fR). This makes for admittedly more sustainable
  source code for an editor who lacks knowledge of Roff.

* A basic macro has been added to insert highlighted URLs with less line
  noise. To insert a bold and underlined URL on a new line, one only has
  to write ".ur http://…"

PR-URL: #7819
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>

doc/node.1

@@ -1,10 +1,28 @@
 .TH NODE 1 2016 Node.js Node.js
 
-.\ This is a man page comment.
-.\ Man page syntax (actually troff syntax) is somewhat obscure, but the
-.\ important part is is that .<letter> specifies <letter>'s syntax for that
-.\ line, and \f<letter> specifies it for the characters that follow.
-.\ See http://liw.fi/manpages/ for more info.
+.\" This is a man page comment.
+
+.\" Man page syntax (actually roff syntax) is somewhat obscure, but the
+.\" important part is is that .<letter> specifies <letter>'s syntax for that
+.\" line, and \f<letter> specifies it for the characters that follow.
+
+.\" .B   Bold line
+.\" .I   Italic line (Rendered as underlined text in terminals)
+.\" .BI  Alternating bold/italics without spaces between arguments.
+.\"      Use `\ ` to include an "unpaddable" (literal) space in the output.
+.\" .RI  Alternating roman/italic
+
+.\" See http://liw.fi/manpages/ for an overview, or http://www.troff.org/54.pdf
+.\" for detailed language reference.
+
+.\" Macro to display an underlined URL in bold
+.de ur
+.nr CF \\n(.f
+.ft 4
+\\$1
+.ft \\n(CF
+..
+
 
 .SH NAME
 
@@ -14,15 +32,22 @@ node \- Server-side JavaScript runtime
 .SH SYNOPSIS
 
 .B node
-[\fIoptions\fR] [\fIv8 options\fR]
-[\fIscript.js\fR | \fB\-e \fR"\fIscript\fR"]
-[\fIarguments\fR]
+.RI [ options ]
+.RI [ v8\ options ]
+.RI [ script.js \ |
+.B -e
+.RI \&" script \&"]
+.RI [ arguments ]
 .br
 .B node debug
-[\fIscript.js\fR | \fB\-e \fR"\fIscript\fR" | \fI<host>:<port>\fR] \fI...
+.RI [ script.js " | "
+.B \-e
+.RI \&" script \&"\ |
+.IR <host>:<port> ]
+.I ...
 .br
 .B node
-[\fB\-\-v8-options\fR]
+.RB [ \-\-v8-options ]
 
 Execute without arguments to start the REPL.
 
@@ -136,14 +161,20 @@ value to an empty string ("" or " ") disables persistent REPL history.
 
 .SH RESOURCES AND DOCUMENTATION
 
-Website: \fBhttps://nodejs.org/\fR
+Website:
+.ur https://nodejs.org/
 
-Documentation: \fBhttps://nodejs.org/api/\fR
+Documentation:
+.ur https://nodejs.org/api/
 
-GitHub repository & Issue Tracker: \fBhttps://github.com/nodejs/node\fR
+GitHub repository & Issue Tracker:
+.ur https://github.com/nodejs/node
 
-Mailing list: \fBhttp://groups.google.com/group/nodejs\fR
+Mailing list:
+.ur http://groups.google.com/group/nodejs
 
-IRC (general questions): \fBchat.freenode.net #node.js\fR
+IRC (general questions):
+.ur "chat.freenode.net #node.js"
 
-IRC (node core development): \fBchat.freenode.net #node-dev\fR
+IRC (node core development):
+.ur "chat.freenode.net #node-dev"