Upgrade the book installer help

Add a new feature to the @skills/book-installer called "help" - when the user asks "what does the
book-installer skill do" it should return a list of all the cool things that the book-installer can do
to add new features to the mkdocs book. Start with things like "Adding support for equations", "Adding
support for social previews" "Adding support for social preview image overrides", "Adding support for
quizzes", "Add support for custom prompt admonitions with copy" etc. The list should allow the user to
start with a minimal mkdocs.yml file but the skill should have rules for enriching the mkdocs.yml file
to add the new features. Also add a line for "Add support for code highlighting" and "Add support for
simple feedback" and "Add support for detailed comment feedback" and "Add support for image zoom on
click"