ensure calls to equal-or-member function use org-latex-impatient

[dankessler]

org-latex-impatient provides a useful function called org-latex-impatient--equal-or-member, which it calls in a few places. however, in some places (mostly in code handling markdown mode), it instead calls yang/equal-or-member. I assume this is an artifact of the development cycle and that the latter is a function available to the developer, but not in the package. I've simply renamed any instances of yang/equal-or-member to org-latex-impatient--equal-or-member.