[DOC] Improve documents related to Helium

[tae-jun]

What is this PR for?

What I did for the documents:

• Highlight codes
• Follow JSON syntax
• Remove white spaces

And in my opinion, here is ambiguous:

"Normally, you can add any dependencies in package.json however Zeppelin Visualization package only allows two dependencies: zeppelin-vis and zeppelin-tabledata."

Does it want to say "you can add any dependencies in package.json, but you must include two dependencies: zeppelin-vis and zeppelin-tabledata."?

What type of PR is it?

[Documentation]

Questions:

• Does the licenses files need update? NO
• Is there breaking changes for older versions? NO
• Does this needs documentation? NO

[AhyoungRyu]

@tae-jun Thanks for the improvement.

You can add any dependencies in package.json, but you must include two dependencies: zeppelin-vis and zeppelin-tabledata.

Yeah I think you're right.

[tae-jun]

@AhyoungRyu Thanks for the review!

I changed the sentence, and now it looks like this:

You can add any dependencies in package.json, but you must include two dependencies: zeppelin-vis and zeppelin-tabledata.

I marked it as bold, since I think it's important 😄

[AhyoungRyu]

@tae-jun Looks GOOD to merge :)

[tae-jun]

@AhyoungRyu Thanks! 👍

[AhyoungRyu]

Merge into master if there are no more comments on this.