doc: now we highly recommend Test::Nginx::Socket.

Author: agentzh

README.md

@@ -21,7 +21,7 @@ Table of Contents
 
 This distribution provides two testing modules for Nginx C module development:
 
-- [Test::Nginx::Socket](https://metacpan.org/pod/Test::Nginx::Socket) (This is recommended.)
+- [Test::Nginx::Socket](https://metacpan.org/pod/Test::Nginx::Socket) (This is highly recommended.)
 - [Test::Nginx::LWP](https://metacpan.org/pod/Test::Nginx::LWP) (This is obsolete.)
 
 All of them are based on [Test::Base](https://metacpan.org/pod/Test::Base).

lib/Test/Nginx.pm

@@ -21,7 +21,7 @@ This distribution provides two testing modules for Nginx C module development:
 
 =item *
 
-L<Test::Nginx::Socket> (This is recommended.)
+L<Test::Nginx::Socket> (This is highly recommended.)
 
 =item *