nvim.1: Misc. improvements #2758

Prefer typographic single quotes instead of straight double quotes.
This avoids confusion when double quotes are used as part of arguments.

Annotate EOF as a "defined variable".
Assuming mandoc is used, `apropos Dv=EOF` should now work.

Clarify in parentheses what a hyphen is, as users might only know it
as a "dash". The same was already done for colons.

Group environment variables more logically.

Reviewed-by: Felipe Morales <hel.sheep@gmail.com>
Reviewed-by: Ian Ker-Seymer <i.kerseymer@gmail.com>

man/nvim.1

@@ -1,4 +1,4 @@
-.Dd May 13, 2015
+.Dd May 28, 2015
 .Dt NVIM 1
 .Os Neovim
 .Sh NAME
@@ -24,7 +24,7 @@ is a text editor based on
 To enter commands in
 .Nm ,
 type a colon
-.Qq ( Cm \&: ) ,
+.Pq Sq \&:
 which is also used in this manual to denote commands.
 For more information, consult the on-line help system with the
 .Ic :help
@@ -40,7 +40,9 @@ and
 .Ic :previous
 commands.
 .It Fl
-Read text from standard input until EOF, then open a buffer with that text.
+Read text from standard input until
+.Dv EOF ,
+then open a buffer with that text.
 Commands are read from standard error, which should be a terminal.
 .It Fl t Ar tag
 The file to edit and the initial cursor position depends on a
@@ -70,7 +72,8 @@ See
 .It There are a number of other options:
 .It Fl -
 Interpret all further arguments as files.
-Can be used to edit files starting with a hyphen.
+Can be used to edit files starting with a hyphen
+.Pq Sq - .
 .It Fl -literal
 Interpret filenames literally, that is do not expand wildcards.
 Has no effect on UNIX-like systems, where the shell expands wildcards.
@@ -164,7 +167,9 @@ Recovery mode.
 The swap file
 .Ar file
 is used to recover a crashed session.
-The swap file has the same filename as the text file, but with ".swp" appended.
+The swap file has the same filename as the text file, but with
+.Sq .swp
+appended.
 See
 .Ic :help recovery .
 .It Fl u Ar nvimrc
@@ -298,7 +303,8 @@ after the first file argument has been read.
 Equivalent to
 .Cm -c \(dqsource session\(dq .
 .Ar session
-cannot start with a hyphen.
+cannot start with a hyphen
+.Pq Sq - .
 If
 .Ar session
 is omitted, then
@@ -345,6 +351,11 @@ Print version information and exit.
 .El
 .Sh ENVIRONMENT
 .Bl -tag -width Fl
+.It Ev VIM
+Used to locate various user files, such as the user's nvimrc.
+.It Ev VIMRUNTIME
+Used to locate run time files, such as on-line documentation and
+syntax highlighting definitions.
 .It Ev VIMINIT
 A string of Ex commands to be executed at startup.
 For example, the command to quit is
@@ -354,14 +365,9 @@ so to have
 quit immediately after starting, set
 .Ev VIMINIT
 to
-.Qq Cm q .
+.Cm q .
 See
 .Ic :help VIMINIT .
-.It Ev VIM
-Used to locate various user files, such as the user-local nvimrc.
-.It Ev VIMRUNTIME
-Used to locate run time files, such as on-line documentation and
-syntax highlighting definitions.
 .It Ev SHELL
 Used to set the 'shell' option, which determines the shell used by the
 .Ic :terminal