style.mdoc: Li macro is undeprecated for some time

Previously, the mdoc linter warned against using Li as it was deprecated
upstream. However, upstream undeprecated it since last year. As usual
when it comes to style, the best thing to do is to follow the existing
style of the page. We have many manuals which prefer double quotes.

MFC after:		3 days
Citation:		https://cvsweb.bsd.lv/mandoc/mdoc.7?rev=1.297
Differential Revision:	https://reviews.freebsd.org/D55297

share/man/man5/style.mdoc.5

@@ -3,7 +3,7 @@
 .\"
 .\" SPDX-License-Identifier: BSD-2-Clause
 .\"
-.Dd October 24, 2025
+.Dd February 16, 2025
 .Dt STYLE.MDOC 5
 .Os
 .Sh NAME
@@ -41,14 +41,6 @@ which renders as:
 Then run
 .Ql Nm make Cm install Cm clean .
 .Ed
-.It
-The
-.Sy \&Ql
-macro is the preferred macro for formatting literal inline fragments.
-Historically,
-.Sy \&Dq \&Li
-was the preferred way before the deprecation of
-.Sy \&Li .
 .El
 .Ss Copyright Header
 Refer to