KCL: stdlib macro should now assume all functions use keywords (#7158)

This has been enforced by the parser since #6639, so there's no need for `keywords = true` in every stdlib function anymore.

rust/kcl-derive-docs/tests/doc_comment_with_code.gen

@@ -93,10 +93,6 @@ impl crate::docs::StdLibFn for MyFunc {
         vec![]
     }
 
-    fn keyword_arguments(&self) -> bool {
-        false
-    }
-
     fn args(&self, inline_subschemas: bool) -> Vec<crate::docs::StdLibFnArg> {
         let mut settings = schemars::gen::SchemaSettings::openapi3();
         settings.inline_subschemas = inline_subschemas;