Add mkdocs for docs

docs/programmers/api-functions/api-fetch.md

@@ -69,7 +69,7 @@ The `email_body.tpl` template
 
         
 
-The php script using the PHP [`mail()`](&url.php-manual;function.mail)
+The php script using the PHP [`mail()`](https://www.php.net/function.mail)
 function
 
 

docs/programmers/api-functions/api-mute-expected-errors.md

@@ -10,7 +10,7 @@ string
 muteExpectedErrors
 
 muteExpectedErrors() registers a custom error handler using
-[set\_error\_handler()](&url.php-manual;set_error_handler). The error
+[set\_error\_handler()](https://www.php.net/set_error_handler). The error
 handler merely inspects `$errno` and `$errfile` to determine if the
 given error was produced deliberately and must be ignored, or should be
 passed on to the next error handler.