Update linear_search.c

[kharajch]

Description of Change

1. If The Element Is Found - linearsearch() function will return the index of that element which will later get printed out through the main() function.

2. If The Element Is Not Found - linearsearch() function will return 0.

References

#1544

Checklist

• Added description of change
• Added file name matches File name guidelines
• Added tests and example, test must pass
• Relevant documentation/comments is changed or added
• PR title follows semantic commit guidelines
• Search previous suggestions before making a new one, as yours may be a duplicate.
• I acknowledge that all my contributions will be made under the project's license.

Notes: Issue Resolved Successfully