Function get_declaring_method 

pub fn get_declaring_method<'a>(
    codebase: &'a CodebaseMetadata,
    fqcn: &str,
    method_name: &str,
) -> Option<&'a FunctionLikeMetadata>

Retrieves the metadata for a method, searching the inheritance hierarchy.

This function finds where the method is declared (which could be an ancestor class/trait) and returns the metadata from there.

The lookup for both the class-like name and the method name is case-insensitive.