I suggest to replace this:
"Every piece of LilyPond input needs to have {curly braces} placed
around the input. For the rest of this manual, most examples will omit
these braces, but don't forget them in your own music!"
with this (also note the inserted whitespace around "curly braces"):
"Every piece of LilyPond input needs to have { curly braces } placed
around the input. The braces should be surrounded by a space unless
they are at the beginning or end of a line to avoid ambiguities. For
the rest of this manual, most examples will omit these braces, but
don't forget them in your own music!"