Improved BubbleSort and added doctests to it

[marsonya]

Welcome to JavaScript community

Describe your change:

Here are the changes I made in the Sorts/BubbleSort.js file:

• Added Wikipedia Link.
• Improved Comments and Formatting.
• The first BubbleSort (using 2 for loops) was not returning the array. Changed that.
• Improved the Implementation Examples and Console logs.
• And Finally, added doctests as mentioned in (Issue #142)

• Add an algorithm?
• Fix a bug or typo in an existing algorithm?
• Documentation change?

Checklist:

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized.
• 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 JavaScript files are placed inside an existing directory.
• All filenames should use the UpperCamelCase (PascalCase) style. There should be no spaces in filenames.
  Example:UserProfile.js is allowed but userprofile.js,Userprofile.js,user-Profile.js,userProfile.js are not
• All new algorithms have a URL in its comments that points to Wikipedia or other similar explanation.
• If this pull request resolves one or more open issues then the commit message contains Fixes: #{$ISSUE_NO}.