[PATCH] fix ")fin" for ECL

[Qian Yun]

This patch adds "(si:top-level)" to the end of
"top-fun" of FriCAS built with ECL.

So that when typing ")fin" we are returned to ECL
REPL instead of loop.

This is similar to CCL,
https://github.com/fricas/fricas/blob/5a7a56aab971354823c20eace6d532396dd8a176/src/lisp/fricas-lisp.lisp#L133

I also updated documentation and FAQ.

I also improved the back-quoting in *fricas-initial-lisp-forms*.

- Qian

[Waldek Hebisch]

OK, please commit.

--
Waldek Hebisch