Replace generic Exception with ValueError in linear_search

[anureetkaur55]

Description

Replaced the generic Exception with ValueError in rec_linear_search() for more specific and Pythonic error handling.

Also improved the docstring wording for better readability.

Changes Made

• Replaced Exception with ValueError
• Improved docstring description

Type of Change

• Code quality improvement
• Documentation improvement

[algorithms-keeper]

Closing this pull request as invalid

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