Improve detection of inherited documentation comments for parameter and return validation

[d-ronnqvist]

Bug/issue #, if applicable: rdar://134534169

Summary

This uses the same logic that DocC uses elsewhere to detect if a documentation comment is inherited from the current module to avoid validating parameters and return values for inherited documentation comments. Theses warnings won't be actionable since their location isn't from this module's code.

Dependencies

None.

Testing

Build documentation for Outer.docc.zip and pass --enable-inherited-docs.
There shouldn't be any parameter or return value warnings emitted.

If you want to recreate Outer.symbols.json;

• Define two modules; an inner and an outer where the outer depend on the inner.

• In the inner module, define a protocol with a func that has parameter and return value warnings:

// in Inner

public protocol SomeProtocol {
    /// A documentation comment with warnings
    /// - Parameter notFound: This parameter does not exist.
    /// - Returns: This function doesn't return anything.
    func someMethod()
}

• In the outer module, conform to that protocol and don't override the documentation comment:

import Inner

public struct SomeStruct: Inner.SomeProtocol {
    // don't override doc comment
    public func someMethod() {}
}

Checklist

Make sure you check off the following items. If they cannot be completed, provide a reason.

• Added tests
• Ran the ./bin/test script and it succeeded
• Updated documentation if necessary Not applicable.

[d-ronnqvist]

@swift-ci please test

[d-ronnqvist]

@swift-ci please test