Chapter 5: restore mention of {bo} grouping in section on NAhE, and add {bo} to one example

[mezohe]

Related to line 12 of Ilmen's review notes: https://framateam.org/files/otkx5nd9jjbkuxwajjiuufe7ew/public?h=WDCE0pu0bYHRkjm7wMKh_G_LIuG36ekA4lkIHtsQwB0

Also includes cleanup of extra spacing around punctuation that was added during an auto-format.