Fix issue #47101

[tigerhawkvok]

Bisecting two years ago ( #47101 (comment) ) shows this regression was introduced in b2d54d9 in 2021. Somehow this hasn't been patched since then.

PR #48313 was supposed to address this, but the PR was closed and never merged and the bug has persisted.

Patch takes two tracks -- it first replaces the arr == x with np.equals() which will handle broadcasting in most cases by itself. For the remainder of cases, an explicit type check is done to return an array for the mask.

• closes BUG: AttributeError: 'bool' object has no attribute 'to_numpy' in "mask_missing" method of core/missing.py #47101
• Tests added and passed if fixing a bug or adding a new feature
• All code checks passed.
• Added type annotations to new arguments/methods/functions.
• Added an entry in the latest doc/source/whatsnew/vX.X.X.rst file if fixing a bug or adding a new feature.

[tigerhawkvok]

I honestly don't understand what failed here

ruff-format.............................................................................................Failed
- hook id: ruff-format
- files were modified by this hook

[mroeschke]

Thanks for the pull request, but it appears to have gone stale. If interested in continuing, please merge in the main branch, address any review comments and/or failing tests, and we can reopen.

[tigerhawkvok]

Thanks for the pull request, but it appears to have gone stale. If interested in continuing, please merge in the main branch, address any review comments and/or failing tests, and we can reopen.

Reopened as #59766 @mroeschke