Request to revise a sentence for better accessibility of users

[JinchunChoi]

Hi. I found one sentence to revise for better accessibility of users.

I think the gap between instruction and actual UI since the update of UI, I'm not sure.

Please see the below and review my revision.

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Location:
non-profit-blockchain/ngo-ui/README.md

Section:
Step 4 - Start the application

Before:
"In Cloud9, navigate to the Cloud9 menu and click Preview->Preview Running Application."

After:
"In Cloud9, navigate to the Cloud9 menu and click Tools->Preview->Preview Running Application."

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Thank you very much.

[JinchunChoi]

Oh, I found the "Preview" button exists on the Cloud9 menu bar, too.
We may add an explanation in case.