the article has a tricky typo here. it says "The keystroke `I` insert text after the first non-blank characters of the line." but it should say _before_ the fi

the article has a tricky typo here. it says "The keystroke `I` insert text after the first non-blank characters of the line." but it should say _before_ the first non-blank, which is equivalent to _after_ the last leading blank.