Merge branch 'ah/doc-gitattributes-empty-index'

An example in documentation that does not work in multi worktree
configuration has been corrected.

* ah/doc-gitattributes-empty-index:
  doc: do not use `rm .git/index` when normalizing line endings

Author: gitster

Documentation/gitattributes.txt

@@ -229,7 +229,7 @@ From a clean working directory:
 
 -------------------------------------------------
 $ echo "* text=auto" >.gitattributes
-$ rm .git/index     # Remove the index to re-scan the working directory
+$ git read-tree --empty   # Clean index, force re-scan of working directory
 $ git add .
 $ git status        # Show files that will be normalized
 $ git commit -m "Introduce end-of-line normalization"