make tut doc ever so slightly less hideous

[tpolecat]

This PR adds the :silent modifier to code blocks that contain only definitions (and in a few cases splits mixed blocks). The resulting tut doc is much cleaner.

[tpolecat]

This compile error wasn't detected because the file ended with a code block without a closing } so the REPL was left hanging. Nice work isolating a corner case!

[ceedubs]

For the record, this is because of tpolecat/tut#65.

[codecov-io]

Current coverage is 85.01%

Merging #709 into master will not affect coverage as of 910e7e5

@@            master    #709   diff @@
======================================
  Files          162     162       
  Stmts         2229    2229       
  Branches        74      74       
  Methods          0       0       
======================================
  Hit           1895    1895       
  Partial          0       0       
  Missed         334     334       

Review entire Coverage Diff as of 910e7e5

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[ceedubs]

Wow, thanks for going through and doing this, @tpolecat! 👍

[adelbertc]

👍