improve man pages

* man/ruby.1, man/erb.1, man/goruby.1, man/irb.1:
  fix document title formatting and volume name,
  improve "REPORTING BUGS" section: fix mdoc formatting error
  (wrong macro for bullet list items), small rewordings.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58411 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

man/erb.1

@@ -1,6 +1,6 @@
 .\"Ruby is copyrighted by Yukihiro Matsumoto <[email protected]>.
 .Dd November 15, 2012
-.Dt ERB(1) "" "Ruby Programmers Reference Guide"
+.Dt ERB \&1 "Ruby Programmer's Reference Guide"
 .Os UNIX
 .Sh NAME
 .Nm erb
@@ -143,15 +143,17 @@ class.
 .Pp
 .Sh REPORTING BUGS
 .Bl -bullet
-.Li Security vulnerabilities should be reported via an email to
-.Aq [email protected] .
+.It
+Security vulnerabilities should be reported via an email to
+.Mt [email protected] .
 Reported problems will be published after being fixed.
 .Pp
-.Li And you can report other bugs and feature requests via the
+.It
+Other bugs and feature requests can be reported via the
 Ruby Issue Tracking System
 .Pq Lk https://bugs.ruby-lang.org/ .
 Do not report security vulnerabilities
-via the system because it publishes the vulnerabilities immediately.
+via this system because it publishes the vulnerabilities immediately.
 .El
 .Sh AUTHORS
 Written by Masatoshi SEKI.

man/goruby.1

@@ -1,6 +1,6 @@
 .\"Ruby is copyrighted by Yukihiro Matsumoto <[email protected]>.
 .Dd November 15, 2012
-.Dt GORUBY(1) "" "Ruby Programmers Reference Guide"
+.Dt GORUBY \&1 "Ruby Programmer's Reference Guide"
 .Os UNIX
 .Sh NAME
 .Nm goruby

man/irb.1

@@ -1,6 +1,6 @@
 .\"Ruby is copyrighted by Yukihiro Matsumoto <[email protected]>.
 .Dd November 15, 2012
-.Dt IRB(1) "" "Ruby Programmers Reference Guide"
+.Dt IRB \&1 "Ruby Programmer's Reference Guide"
 .Os UNIX
 .Sh NAME
 .Nm irb
@@ -159,15 +159,17 @@ Personal irb initialization.
 .Pp
 .Sh REPORTING BUGS
 .Bl -bullet
-.Li Security vulnerabilities should be reported via an email to
-.Aq [email protected] .
+.It
+Security vulnerabilities should be reported via an email to
+.Mt [email protected] .
 Reported problems will be published after being fixed.
 .Pp
-.Li And you can report other bugs and feature requests via the
+.It
+Other bugs and feature requests can be reported via the
 Ruby Issue Tracking System
 .Pq Lk https://bugs.ruby-lang.org/ .
 Do not report security vulnerabilities
-via the system because it publishes the vulnerabilities immediately.
+via this system because it publishes the vulnerabilities immediately.
 .El
 .Sh AUTHORS
 Written by Keiju ISHITSUKA.

man/ruby.1

@@ -1,7 +1,6 @@
 .\"Ruby is copyrighted by Yukihiro Matsumoto <[email protected]>.
 .Dd October 31, 2015
-.Dt RUBY(1) "" "Ruby Programmers Reference Guide"
-.\".Dt RUBY 1
+.Dt RUBY \&1 "Ruby Programmer's Reference Guide"
 .Os UNIX
 .Sh NAME
 .Nm ruby
@@ -641,15 +640,17 @@ Comprehensive catalog of Ruby libraries.
 .Pp
 .Sh REPORTING BUGS
 .Bl -bullet
-.Li Security vulnerabilities should be reported via an email to
-.Aq [email protected] .
-Reported problems will be published after they've been fixed.
+.It
+Security vulnerabilities should be reported via an email to
+.Mt [email protected] .
+Reported problems will be published after being fixed.
 .Pp
-.Li And you can report other bugs and feature requests via the
+.It
+Other bugs and feature requests can be reported via the
 Ruby Issue Tracking System
 .Pq Lk https://bugs.ruby-lang.org/ .
 Do not report security vulnerabilities
-via the system because it publishes the vulnerabilities immediately.
+via this system because it publishes the vulnerabilities immediately.
 .El
 .Sh AUTHORS
 Ruby is designed and implemented by