add a warning (exported) function to the core

Signed-off-by: intrigeri <intrigeri@boum.org>

IkiWiki.pm

@@ -21,7 +21,7 @@ our @EXPORT = qw(hook debug error template htmlpage add_depends pagespec_match
                  bestlink htmllink readfile writefile pagetype srcfile pagename
                  displaytime will_render gettext urlto targetpage
 		 add_underlay pagetitle titlepage linkpage newpagefile
-		 inject
+		 inject warning
                  %config %links %pagestate %wikistate %renderedfiles
                  %pagesources %destsources);
 our $VERSION = 3.00; # plugin interface version, next is ikiwiki version
@@ -579,6 +579,10 @@ sub error ($;$) {
 	die $message."\n";
 }
 
+sub warning ($) {
+	return log_message(warning => @_);
+}
+
 sub debug ($) {
 	return unless $config{verbose};
 	return log_message(debug => @_);

doc/plugins/write.mdwn

@@ -555,6 +555,10 @@ the id can be controled by the user.
 Logs a debugging message. These are supressed unless verbose mode is turned
 on.
 
+#### `warning($)`
+
+Logs a warning message.
+
 #### `error($;$)`
 
 Aborts with an error message. If the second parameter is passed, it is a