p5bots file naming discrepancy in HelloWorld.md

[ncmikkelsen]

The HelloWorld guide makes a reference to the p5bots file being named p5.bots.js while the code snippet for the index.html references a file named p5bots.js.

This makes the example throw a TypeError: p5.board is not a function and a TypeError: b is undefined. It's a simple fix just renaming either the file itself or the reference to the file but I suspect this could cause issues for beginners.

[ncmikkelsen]

I realize that this is only an issue because the file doesn't download automatically (atleast for me it didn't) but just displays the content of the file in the browser.