LANG-1806: Allow floating-point suffixes in NumberUtils.isParsable

[Jagdish-Singh-Bisht]

This PR addresses LANG-1806 as a small follow-up to LANG-1695.

NumberUtils.isParsable currently rejects strings such as "1.f" and "1.d", even though Float.parseFloat("1.f") and Double.parseDouble(1.d") succeed.

The test suite already contained TODOs for these cases, this change uncomments those assertions and updates the parsing logic to allow floating-point suffixes (f/F/d/D) only when they appear as the final character.

The change is intentionally minimal and doesn not affect other numeric formats.

[garydgregory]

Hello @Jagdish-Singh-Bisht

This PR doesn't handle:

• 1.2e-5d
• 1.2e-5f

You did not follow the instructions in the PR template:

• Run mvn
• Fix all errors
• Also remove the extra blank lines.

Rebase on git master where I added test TODOs for the above.

[Jagdish-Singh-Bisht]

Thanks for the review.

Understood regarding the scientific notation cases (1.2e-5d / 1.2e-5f).
I'll rebase on current master, address those cases, clean-up formatting, and confirm mvn test before updating the PR.

[Jagdish-Singh-Bisht]

Thanks for the review and guidance.

I have rebased on the latest master, cleaned up formatting, and verified the build with mvn test.

This PR intentionally limits the scope to suffix-only cases(2.f, 2.d) as a minimal follow-up to LANG-1695.
The cases (1.2e-5f, 1.2e-5d) remain as TODOs added on master, since they would require additional exponent-parsing logic
and may be better addressed separately.

Please let me know if you'd prefer those cases to be handled in this PR.

[garydgregory]

@Jagdish-Singh-Bisht
Still -1: I have the same comment as before: We don't need to have a special case for this one kind of float since we know it doesn't work for numbers like 1.2e-5d and 1.2e-5f. Fix it all here please.

[Jagdish-Singh-Bisht]

I have pushed the updated implementation that fully supports scientific notation with float/double suffixes.
Please let me know if anything else is needed.

[garydgregory]

Hello @Jagdish-Singh-Bisht

Thank you for updating your PR. Unfortunately, you did not follow the instructions in the PR template. You must run mvn by itself to validate your changes, which in this case, will fail the Checkstyle portion of the build.

I was thinking of something simpler, using a regular expression: Please test #1560 for your use case and me know if that works in your application.

[garydgregory]

Closing: No reply. Implemented in git master with #1560