Update coding style guidelines for function arguments

Added guidelines for using arrays as function arguments, emphasizing explicit parameter listing and type definition.

Author: traviswindsormoodle

general/development/policies/codingstyle/index.md

@@ -1159,6 +1159,37 @@ Magic methods are heavily discouraged, justification will be required when used.
 
 (See [MDL-52634](https://moodle.atlassian.net/browse/MDL-52634) for discussion of rationale)
 
+### Using arrays for options as arguments
+
+All arguments to a function should be explicitly listed out and defined with a type. Using arrays like this can result in error as the types are not enforced as well as leading to poor documentation of the function
+
+<InvalidExample>
+```php
+    public function badfunction(
+        string $text,
+        context $context = null,
+        array $options = [],
+    ): string;
+</InvalidExample>
+
+If arguments are optional, then they should be marked appropriately as optional with a default value. 
+<ValidExample>
+    function goodfunction(
+        string $text,
+        ?context $context = null,
+        bool $trusted = false,
+        ?bool $clean = null,
+        bool $filter = true,
+        bool $para = true,
+        bool $newlines = true,
+        bool $overflowdiv = false,
+        bool $blanktarget = false,
+        bool $allowid = false,
+    ): string;
+</ValidExample>
+
+If there was a very good reason, then the use of an array could be considered. But it is strongly encouraged that all parameters be explict and typed.
+
 ## Control statements
 
 In general, use white space liberally between lines to add clarity.