style.mdoc.5: Suggest preferred formatting for EXAMPLES

Add an example of how to format examples in EXAMPLES sections. The
suggested format is heavily based on zfs.8.

While here, capitalize subsection titles.

Reviewed by:	bcr
Approved by:	bcr (doc),
Approved by:	krion (mentor, implicit), mat (mentor, implicit)
Differential Revision:	https://reviews.freebsd.org/D18681

share/man/man5/style.mdoc.5

@@ -26,7 +26,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd December 28, 2018
+.Dd December 29, 2018
 .Dt STYLE.MDOC 5
 .Os
 .Sh NAME
@@ -39,7 +39,7 @@ file style guide
 This file specifies the preferred style for manual pages in the
 .Fx
 source tree.
-.Ss Code examples
+.Ss Code Examples
 .Bl -dash -width ""
 .It
 Use literal formatting for examples and literal shell commands, e.g.:
@@ -68,7 +68,53 @@ Then run
 .Dq Nm make Cm install Cm clean .
 .Ed
 .El
-.Ss Synopsis formatting
+.Ss EXAMPLES Section
+.Bl -dash -width ""
+.It
+Format the
+.Sx EXAMPLES
+section in the following way:
+.Bd -literal -offset indent
+\&.Bl -tag -width 0n
+\&.It Sy Example 1\&: No Doing Something
+\&.Pp
+The following command does something.
+\&.Bd -literal -offset 2n
+\&.Li # Ic make -VLEGAL
+\&.Ed
+\&.It Sy Example 2\&: No Doing Something Different
+\&.Pp
+The following command does something different.
+\&.Bd -literal -offset 2n
+\&.Li # Ic bectl list
+\&.Ed
+\&.Pp
+It is good to know this command.
+\&.El
+\&.El
+.Ed
+.Pp
+which renders as:
+.Bd -filled -offset indent
+.Bl -tag -width 0n
+.It Sy Example 1\&: No Doing Something
+.Pp
+The following command does something.
+.Bd -literal -offset 2n
+.Li # Ic make -VLEGAL
+.Ed
+.It Sy Example 2\&: No Doing Something Different
+.Pp
+The following command does something different.
+.Bd -literal -offset 2n
+.Li # Ic bectl list
+.Ed
+.Pp
+It is good to know this command.
+.El
+.Ed
+.El
+.Ss Synopsis Formatting
 .Bl -dash -width ""
 .It
 Do not put whitespace between alternative parameters separated with a pipe