Add Longest Word in Julia

[brittLiban]

I Am Adding a New Code Snippet in an Existing Language

• [x] I fixed #3988
• [x] I named the pull request using Add {PROJECT} in {LANGUAGE} format

Other Notes

• Thanks for letting our Sdev 301 class participate!
• The implementation reads a single command-line argument as the input string.
• It replaces newline, tab, and carriage return characters with spaces, as required.
• If the input is empty or no argument is provided, the program outputs the usage message: "Usage: please provide a string."