Options for URL matching and output

The code considers the href and text to be the same for both these cases:

(A) <a href="https://a.b.c">a.b.c</a>
(B) <a href="http://a.b.c">a.b.c</a>

Both are rendered as 'a.b.c'

However it does not consider the following to be the same:

(C) <a href="http://a.b.c/">a.b.c</a>

So the output is rendered as '[a.b.c](http://a.b.c/)'

I think the href in (A) should not be considered equal, whereas I expect (C) to render as 'a.b.c'.

For some circumstances, it might also be useful to keep the '[text](url)' format regardless of equality.

Maybe it would be useful to do the URL matching in a separate function that could optionally be provided by callers?

Additionally perhaps allow the output format to be varied, e.g. as
'text <url>' which seems to be common in text portions of mime mails.

No file, test, or entry point is named. Start by locating the URL comparison and output-format handling, then clarify which matching rules and output formats are required before defining tests that cover the proposed cases and confirm the chosen behavior.