Fix/37601 Add aria-describedby to Select options button

[faisal-alvi]

Submission Review Guidelines:

• I have followed the WooCommerce Contributing Guidelines and the WordPress Coding Standards.
• I have checked to ensure there aren't other open Pull Requests for the same update/change.
• I have reviewed my code for security best practices.
• Following the above guidelines will result in quick merges and clear and detailed feedback when appropriate.

Changes proposed in this Pull Request:

• This PR adds a function to get the aria-describedby description for the add to cart button.
• Also adds default description for the Select options button.

Closes #37601.

How to test the changes in this Pull Request:

Using the WooCommerce Testing Instructions Guide, include your detailed testing instructions:

1. Go to the Shop page.
2. Inspect the button "Select options"
3. Check the aria-describedby attribute is added with the value: "This product has multiple variants. The options may be chosen on the product page".

[jorgeatorres]

Hi @faisal-alvi!

Thanks for your contribution 💯. I tested and while this works when the default "Select options" string is used, it doesn't really work if that string changes (for example, when translated).

I left some comments on how to possibly fix that, as well as some general (though easily solved) feedback.

Please let me know what you think. Looking forward to hearing back from you.

[jorgeatorres]

There's no need to check that the key is set with isset(). empty() already takes care of that.

[faisal-alvi]

@jorgeatorres thanks for the feedback. The suggestions/changes are implemented. Please check 99b5c7e and let me know if any changes are required.

[github-actions]

Hi ,

Apart from reviewing the code changes, please make sure to review the testing instructions as well.

You can follow this guide to find out what good testing instructions should look like:
https://github.com/woocommerce/woocommerce/wiki/Writing-high-quality-testing-instructions

[codecov]

Codecov Report

Merging #37880 (1b04c2f) into trunk (924c871) will decrease coverage by 0.0%.
The diff coverage is 5.9%.

Additional details and impacted files

@@            Coverage Diff             @@
##             trunk   #37880     +/-   ##
==========================================
- Coverage     51.5%    51.5%   -0.0%     
- Complexity   17281    17443    +162     
==========================================
  Files          430      440     +10     
  Lines        80030    80290    +260     
==========================================
+ Hits         41217    41346    +129     
- Misses       38813    38944    +131     

Impacted Files	Coverage Δ
...ommerce/includes/abstracts/abstract-wc-product.php	88.0% <0.0%> (-0.3%)	⬇️
.../woocommerce/includes/admin/wc-admin-functions.php	41.3% <0.0%> (ø)
...woocommerce/includes/class-wc-product-variable.php	75.7% <0.0%> (-0.7%)	⬇️
.../woocommerce/includes/class-wc-structured-data.php	0.0% <0.0%> (ø)
...ins/woocommerce/includes/wc-template-functions.php	12.2% <0.0%> (+0.1%)	⬆️
plugins/woocommerce/includes/wc-core-functions.php	63.6% <100.0%> (ø)

... and 41 files with indirect coverage changes

[jorgeatorres]

LGTM. Thank you @faisal-alvi!

(I just made a tiny change to address a PHPCS issue, but other than that, it looked good)