[BUG] The description of pickaxe in git-blame(1) is wrong

I think that the description of how 'pickaxe' feature works in Documentation/git-blame.txt is wrong. It says:

  Apart from supporting file annotation, git also supports searching the
  development history for when a code snippet occurred in a change. This makes it
  possible to track when a code snippet was added to a file, moved or copied
  between files, and eventually deleted or replaced. _It works by searching for
  a text string in the diff_. A small example:

The part "It works by searching for a text string in the diff" is, if I remember correctly, wrong. Actually it (I think) compares how many matches are in pre-image and in post-image, and shows these commits where those number differ.

This for example means that pickaxe would not pick commit which moved a fragment from one place to other without change, I think.