Add support to rst_epilog from Sphinx #1047
Description
Describe the feature you'd like to request
Sphinx has a configuration called rst_epilog that is described as
A string of reStructuredText that will be included at the end of every source file that is read. This is a possible place to add substitutions that should be available in every file (another being rst_prolog).
rst_epilog is a possible place for shared links across the Sphinx project. With a few Python instructions, rst_epilog can be the content of a file, e.g.
with open("hyperlink-targets.md", encoding="utf-8") as _hyperlink_targets:
rst_epilog = _hyperlink_targets.read()
Describe the solution you'd like
At the moment, Sphinx calls myst-parser before use rst_epilog.
Describe alternatives you've considered
No response