feat: Add NearestElement stack algorithms and fix Javadoc build warnings

[sabarirajan83]

Description

This PR introduces NearestElement.java, which provides stack-based algorithms to efficiently find the nearest greater or smaller elements in an array (for both left and right directions).

• Implements a Monotonic Stack approach to achieve O(n) time complexity.
• Includes explicit safety checks (using short-circuit evaluation and ternary operators) to prevent EmptyStackException.
• Includes comprehensive JUnit 5 tests in NearestElementTest.java.

Additionally, this PR fixes pre-existing documentation comment is not attached to any declaration errors in:

• AnyBaseToAnyBase.java
• InterpolationSearch.java
• LinearSearch.java

These documentation changes ensure strict build compatibility with modern JDK versions (JDK 21+).

Fixes #7322

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized it.
• All filenames are in PascalCase.
• All functions and variable names follow Java naming conventions.
• All new algorithms have a URL in their comments that points to Wikipedia or other similar explanations.
• All new algorithms include a corresponding test class that validates their functionality.
• All new code is formatted with clang-format -i --style=file path/to/your/file.java