Remove "experimental" comment for interpreter args (#189)

This issue has been fixed a long time ago.
Closes #189

docs/UserManual.md

@@ -242,8 +242,6 @@ Note that PHP scripts must use `php-cgi.exe` as executable, not `php.exe`.
 ### cgi\_interpreter\_args
 Optional additional arguments passed to a Windows CGI interpreter program.
 
-(Currently experimental - https://github.com/civetweb/civetweb/issues/854)
-
 ### cgi\_pattern `**.cgi$|**.pl$|**.php$`
 All files that match `cgi_pattern` are treated as CGI files. The default pattern
 allows CGI files be anywhere. To restrict CGIs to a certain directory,