hello, 
here some more remarks from me:

*I discovered the existence of the command `z' very lately, because I read the commands from a to z. Maybe it would be a solution for this to introduce it in the `Introduction to line editing', chapter 2.
*chapter 5,Regular Expressions: "leftmost longest match" is not really clear, which attribute is more important. I understood it as the left-most of the longest matches, but obviously it is the longest of the left-most matches.
*what does "nested" mean in the context of ¨nested subexpression"?
* in the '*' part: "or THE subexpression" rather than "or subexpression" because the last could also mean "or single character subexpression"
*part 'Regular Expressions": change "// repeats last search" into "//repeats the last used term /RE/" because obviously also the /RE/-term in substitutions count.
*"\+": "so the regular expression 'a+' is" replace "a+" by "a\+"


thank you.