final docs callouts (#18843)

<!--
Thanks for taking the time to open a Pull Request (PR)! Please make sure
you've read the "Opening Pull Requests" section of our Contributing
Guide:


https://github.com/Opentrons/opentrons/blob/edge/CONTRIBUTING.md#opening-pull-requests

GitHub provides robust markdown to format your PR. Links, diagrams,
pictures, and videos along with text formatting make it possible to
create a rich and informative PR. For more information on GitHub
markdown, see:


https://docs.github.com/en/get-started/writing-on-github/getting-started-with-writing-and-formatting-on-github/basic-writing-and-formatting-syntax

To ensure your code is reviewed quickly and thoroughly, please fill out
the sections below to the best of your ability!
-->

# Overview

Small PR to add a few final docs callouts before the 8.5 release:
1) adding a link to the [complex
commands](file:///Users/emilyburghardt/opentrons/api/docs/build/html/v2/new_complex_commands.html)
section of the API docs when describing for the first time how to use
`transfer_with_liquid_class()`. @sanni-t pointed out that users might
not know where to find this kind of detail.
2) updating our well bottom warning for
[EXEC-1637](https://opentrons.atlassian.net/jira/software/c/projects/EXEC/issues/EXEC-1637?jql=project%20%3D%20%22EXEC%22%20ORDER%20BY%20created%20DESC).
<!--
Describe your PR at a high level. State acceptance criteria and how this
PR fits into other work. Link issues, PRs, and other relevant resources.
-->

## Test Plan and Hands on Testing

<!--
Describe your testing of the PR. Emphasize testing not reflected in the
code. Attach protocols, logs, screenshots and any other assets that
support your testing.
-->

http://sandbox.docs.opentrons.com/docs-callouts/v2/  

both small changes build with no issues

## Changelog

<!--
List changes introduced by this PR considering future developers and the
end user. Give careful thought and clear documentation to breaking
changes.
-->

## Review requests

<!--
- What do you need from reviewers to feel confident this PR is ready to
merge?
- Ask questions.
-->

Is this sufficient for
[EXEC-1637](https://opentrons.atlassian.net/jira/software/c/projects/EXEC/issues/EXEC-1637?jql=project%20%3D%20%22EXEC%22%20ORDER%20BY%20created%20DESC)?
@caila-marashaj and I discussed keeping this simple, including leaving
it at _all reservoirs_, for extra caution. fix for this should be in
8.6.

## Risk assessment
low. 
<!--
- Indicate the level of attention this PR needs.
- Provide context to guide reviewers.
- Discuss trade-offs, coupling, and side effects.
- Look for the possibility, even if you think it's small, that your
change may affect some other part of the system.
- For instance, changing return tip behavior may also change the
behavior of labware calibration.
- How do your unit tests and on hands on testing mitigate this PR's
risks and the risk of future regressions?
- Especially in high risk PRs, explain how you know your testing is
enough.
-->

[EXEC-1637]:
https://opentrons.atlassian.net/browse/EXEC-1637?atlOrigin=eyJpIjoiNWRkNTljNzYxNjVmNDY3MDlhMDU5Y2ZhYzA5YTRkZjUiLCJwIjoiZ2l0aHViLWNvbS1KU1cifQ

Author: emilyburghardt

api/docs/v2/liquid_classes.rst

@@ -128,6 +128,8 @@ Using Liquid Classes
 
 You'll use a :ref:`liquid class definition <liquid-class-definitions>` in your protocol to optimize transfer behavior based on liquid properties, along with your chosen Flex pipettes and tips. 
 
+This section covers selecting a liquid class and using the :py:meth:`~.InstrumentContext.transfer_with_liquid_class` method. For more details, including using the :py:meth:`~.InstrumentContext.distribute_with_liquid_class` and :py:meth:`~.InstrumentContext.consolidate_with_liquid_class` methods, see :ref:`v2-complex-commands`. 
+
 Start by definining the tips, trash, pipette, and labware used in your transfers. Then, use :py:meth:`.ProtocolContext.get_liquid_class` to select an Opentrons-verified liquid class and save its results to a variable. ``get_liquid_class()`` takes into account the pipette and tip racks in your protocol and only loads the relevant portion of the liquid class definition. 
 
 .. code-block:: python