Docs: three broken Sphinx cross-references (verified against rich 15.0.0)

Summary

Three Sphinx :meth: cross-references in the docs point to symbols that do not exist, so they resolve to dead references (Sphinx: "reference target not found"). Verified against rich 15.0.0 on Python 3.14.

1. docs/source/markup.rst lines 103 and 105 use :meth:~rich.console.Print.print. There is no `Print` class in `rich.console`; the method is `Console.print`. Suggested fix: `:meth:`~rich.console.Console.print.
2. docs/source/console.rst line 368 uses :meth:~rich.ScreenContext.update. `ScreenContext` lives at `rich.console.ScreenContext`, not `rich.ScreenContext`. Suggested fix: `:meth:`~rich.console.ScreenContext.update.

Repro:

• python -c "import rich.console as c; c.Print" -> AttributeError (no Print)
• python -c "import rich; rich.ScreenContext" -> AttributeError (no rich.ScreenContext)
• Correct targets exist under .. automodule:: rich.console: Console.print and ScreenContext.update.

Disclosure

These were found with AI assistance (Claude) and I verified each against the installed rich 15.0.0. Per AI_POLICY.md, I am opening this issue first rather than sending a PR directly. If a maintainer confirms the fix is wanted, I am happy to submit a small PR correcting all three references.