DOC: Sort the pandas API reference navbar in alphabetical order

[DoNguyenHung]

• closes DOC: Sort the pandas API reference navbar in alphabetical order #59164
• 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.

Changes made:

• Added JavaScript to sort only the items in each section of the sidebar and not the section headers.

[mroeschke]

Thanks for the PR, but as noted in the issue it still needs discussion on the solution to move forward so closing