feat: Override link text for code blocks

[KStocky]

This is a proposed fix for #801.

I have made this PR because #820 seems to have been abandoned.

There is a difference in implementation with my PR, though.

Instead of providing another way to specify the URL, this PR proposes to allow writers to override the link text.

Why implement it this way?

By providing a new option called full_url you are giving people another unrelated way of creating URLs that is not compatible with the current way. This may lead to unexpected behaviour (e.g. what should happen if a base_url and full_url are specified?). Additionally, since it would be adding a new way of creating URLs, the logic to implement it is messier.

With the name_override way, we are not introducing a new way of specifying URLs. We are instead just allowing people to override the text of the generated URL with another string.

With this method the URL will ALWAYS be generated with base_url + filename.
With the change being the link text is named_override | default filename

I feel like this is a bit cleaner both in terms of expectations from the user, and from an implementation perspective.

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[imfing]

Thanks for the explanation! The reason I originally preferred the full_url approach is that it allows authors to completely override the generated URL instead of always using base_url as a mandatory prefix.

With the current model, I’m not sure how one could easily support cases where the final URL shouldn't include the base_url at all.

[KStocky]

To be clear, with this approach, base_url can be used as the full URL. base_url + filename still provides the full URL. Except we now allow filename to be empty.

I guess that is the negative to this approach. base_url implies that it can't be the full URL.