Trim docs whitespaces for metadata

[cmichi]

I noticed that our generated contract metadata for the message/constructor docs always contains a space as a prefix to the actual String. I suppose this is because of the parsing logic for /// Foobar.

$ cat flipper.contract | jq ".. | .docs?  | select(.)" | egrep -v "\[|\]"
  " Creates a new flipper smart contract initialized with the given value."
  " Creates a new flipper smart contract initialized to `false`."
  " Flips the current value of the Flipper's bool."
  " Returns the current value of the Flipper's bool."

[ascjones]

Maybe this would be better if there was an inner space e.g. " foo bar ", because this test would also pass with just removing all spaces.

[cmichi]

That's a good point, I'll include this change in another PR.