Attached patch:

     whitespace: Update bob, eob markers in base and indirect buffers

     When a buffer is changed, update `whitespace-bob-marker' and
     `whitespace-eob-marker' not just in the current buffer, but
     also in the base buffer and all of its indirect buffers (if
     any) (Bug#46982).
     * lisp/whitespace.el (whitespace--indirect-buffers,
     whitespace--refresh-indirect-buffers,
     whitespace-unload-function): Track the relationships between
     base buffers and their indirect buffers.
     (whitespace--update-bob-eob-all, whitespace-color-on,
     whitespace-color-off): Define a new function that calls
     `whitespace--update-bob-eob' on the base buffer and all of its
     indirect buffers, and use this new function instead of
     `whitespace--update-bob-eob' in `after-change-functions'.

See Bug#46982 for additional context.  This can also be thought of as a 
continuation of the fix for Bug#59618 made in commit 
d76d7a3bebf1ff0b06a38f7f96d316752844ed10.

I'm not sure if this patch belongs on master, on emacs-29, or nowhere:
   * The bug it fixes is very minor, so it might not be worth the added 
complexity.
   * It touches code that has been the source of a few recent bugs, so 
I'm wary of introducing new bugs onto emacs-29.
   * This is a workaround for Bug#46982; it would be better to fix that 
bug instead (although fixing that bug might be infeasible for reasons of 
backwards compatibility).