DOC: Fix spelling mistakes and incomplete sentences in Timestamp docstrings

[vishwas-droid]

This PR fixes a couple of clear spelling mistakes and a few incomplete or
awkwardly phrased sentences in Timestamp-related docstrings.
These are documentation-only changes and do not affect any behavior or logic.

[vishwas-droid]

@rhshadrach Could you take a look at this and share your thoughts when you have a moment?
Thanks!

[rhshadrach]

Thanks for the PR! The pr-commit build needs to be passing.

[vishwas-droid]

@rhshadrach I've addressed the feedback and everything is in place now. Happy to move forward whenever it looks good to you. Thanks!

[rhshadrach]

lgtm

[vishwas-droid]

Thanks a lot for the review and approval! I really appreciate it.

[rhshadrach]

@vishwas-droid - looks like the tests need update due to the change in the error message.

[vishwas-droid]

@rhshadrach Updated the tests to match the revised error message and the Timestamp wording.

[rhshadrach]

@vishwas-droid the failure of test_parsing_tzlocal_deprecated looks related.

[vishwas-droid]

@rhshadrach
I really appreciate the quick help. I’ve aligned test_parsing_tzlocal_deprecated with the updated "unrecognized timezone" message. I think CI should be green now. Otherwise , I think this is ready to merge. Let me know if any changes are needed.

[rhshadrach]

lgtm

[rhshadrach]

Thanks @vishwas-droid