Rename LetterSound to SoundToLetter?

[jo-elimu]

Should we rename LetterSound to SoundToLetter to clarify its meaning?

When a child learns to read, the process is to match sounds with sequences of letters. This is called "Sound-to-Letter Correspondence."

I propose the following renaming:

• Code: LetterSound --> SoundToLetter
• UI: "Letter-Sound" --> "Sound-to-Letter Correspondence"