fix(doom-docs-org): better icon or notice-credit

The heart emoji degrades to a smaller unicode heart icon in tty Emacs,
causing alignment issues, so I swapped it out for one that has a wider
unicode fallback.

Author: hlissner

doom-docs-org-mode/notice-credit

@@ -3,5 +3,5 @@
 # key: <credit
 # --
 #+begin_quote
- ♥ `%`$0
+ 💕 `%`$0
 #+end_quote