Clarify notation and clean up formatting

[scottw]

Without the appropriate formatting around the sharp and flat scales, this exercise is hard to understand (especially for someone with little or no music theory). For example:

No Accidentals: C major A minor

Use Sharps: G, D, A, E, B, F# major e, b, f#, c#, g#, d# minor

Use Flats: F, Bb, Eb, Ab, Db, Gb major d, g, c, f, bb, eb minor

Because the line breaks are missing, one might go looking for "Gb major d" and wondering how that would be represented in the code.

This PR cleans up the formatting for this critical area, and makes a couple other minor edits (pun intended).