readme edit

[gillyspy]

if this does indeed fold the markdown then i suggest it not be called "code-fold" or perhaps advertised that it is not for folding code snippets but rather editor-fold.

in this tool i don't see the markdown referred to as code
nor the editor referred to as code editor.

searching the docs for "code" yields this:
https://www.google.com/search?hl=en&q=site%3Adocs.inkdrop.app%20code

for "editor" yields this:
https://www.google.com/search?hl=en&q=site%3Adocs.inkdrop.app%20editor