Bold Contribution Guidelines link in README

[Bhoomi070]

Updated README.md to improve formatting and clarity.

Describe your change: [ ] Add an algorithm? [ ] Fix a bug or typo in an existing algorithm? [ ] Add or change doctests? -- Note: Please avoid changing both code and tests in a single pull request. [x] Documentation change?

Checklist: [x] I have read CONTRIBUTING.md. [x] This pull request is all my own work -- I have not plagiarized. [x] I know that pull requests will not be merged if they fail the automated tests. [ ] This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms. [ ] All new Python files are placed inside an existing directory. [ ] All filenames are in all lowercase characters with no spaces or dashes. [ ] All functions and variable names follow Python naming conventions. [ ] All function parameters and return values are annotated with Python type hints. [ ] All functions have doctests that pass the automated testing. [ ] All new algorithms include at least one URL that points to Wikipedia or another similar explanation. [ ] If this pull request resolves one or more open issues then the description above includes the issue number(s) with a closing keyword: "Fixes #ISSUE-NUMBER".

Refactor README.md for better readability