chore: Use both pactffi_set_comment and pactffi_add_text_comment

[tienvx]

pactffi_set_comment does work, but there is a problem. pactffi_add_text_comment is a better replacement for it.

See these links for more information:

• fix: Interaction's comment should be string not array pact-compatibility-suite#8
• Potential new feature - add an optional comments to the interaction pact-specification#45
• feat(ffi): add add_text_comment pact-reference#401

[JP-Ellis]

I think it might be best to extend the commenting functionality, instead of just replacing the current method. I did something similar in Python by adding two methods:

    def set_comment(self, key: str, value: Any | None) -> Self:  # noqa: ANN401
        """
        Set a comment for the interaction.

        This is used by V4 interactions to set a comment for the interaction. A
        comment consists of a key-value pair, where the key is a string and the
        value is anything that can be encoded as JSON.

        Args:
            key:
                Key for the comment.

            value:
                Value for the comment. This must be encodable using
                [`json.dumps(...)`][json.dumps], or an existing JSON string. The
                value of `None` will remove the comment with the given key.

        # Warning

        This function will overwrite any existing comment with the same key. In
        particular, the `text` key is used by `add_text_comment`.
        """
        if isinstance(value, str) or value is None:
            pact.v3.ffi.set_comment(self._handle, key, value)
        else:
            pact.v3.ffi.set_comment(self._handle, key, json.dumps(value))
        return self

    def add_text_comment(self, comment: str) -> Self:
        """
        Add a text comment for the interaction.

        This is used by V4 interactions to set arbitrary text comments for the
        interaction.

        Args:
            comment:
                Text of the comment.

        # Warning

        Internally, the comments are appended to an array under the `text`
        comment key. Care should be taken to ensure that conflicts are not
        introduced by
        [`set_comment`][pact.v3.interaction.Interaction.set_comment].
        """
        pact.v3.ffi.add_text_comment(self._handle, comment)
        return self

This allows end-users to add comments as per the original intentions behind the capability, while also allowing end-users to make use of the full capabilities of the Pact specification.

I would make sure to be really clear in the documentation of the possible way they can interact to hopefully avoid any unexpected side-effects.

[tienvx]

Added method pactffi_set_comment back