DOC: Additions/updates documentation for df.interpolate() methods #60227

[anishkarki]

• closes DOC: Improve documentation df.interpolate() for methods ‘time’, ‘index’ and ‘values’ #60227 (Replace xxxx with the GitHub issue number)
• 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.

This PR improves the documentation for the DataFrame.interpolate() method and closes #60227

The focus is on providing more precise descriptions and examples for the following method options:

• method="index": Emphasized that this method uses the actual numerical values of the index, which is particularly useful for non-sequential or time-based indices.
• method="time": Expanded on the description to specify that this method interpolates based on the time intervals between observations, suitable for data with a time-based index.
• method="values": Clarified that this method performs interpolation based on the actual numerical values within the DataFrame, treating them as equally spaced along the index.

Changes Made

• Enhanced the docstring descriptions for values, index, and time methods in DataFrame.interpolate().
• Added a practical example using a DataFrame with a non-sequential index to demonstrate the difference between method="linear" and method="index".

[anishkarki]

@rhshadrach Could you review this PR to improve documentation for df.interpolate() methods as part of issue #60227?”

[rhshadrach]

Thanks for the PR! I see no difference between "actual numeric values" and "numeric values", so I think "actual" can be removed.

[anishkarki]

@rhshadrach I've made the requested changes to the documentation. Could you please review it again? Thanks!

[rhshadrach]

lgtm

[mroeschke]

Thanks @anishkarki