Update gitattributes docs

Author: AGWA

README

@@ -30,6 +30,7 @@ Specify files to encrypt by creating a .gitattributes file:
 
 	secretfile filter=git-crypt diff=git-crypt
 	*.key filter=git-crypt diff=git-crypt
+	secretdir/** filter=git-crypt diff=git-crypt
 
 Like a .gitignore file, it can match wildcards and should be checked into
 the repository.  See below for more information about .gitattributes.
@@ -148,14 +149,9 @@ specifying merely a directory (e.g. `/dir/`) is NOT sufficient to
 encrypt all files beneath it.
 
 Also note that the pattern `dir/*` does not match files under
-sub-directories of dir/.  To encrypt an entire sub-tree dir/, place the
-following in dir/.gitattributes:
+sub-directories of dir/.  To encrypt an entire sub-tree dir/, use `dir/**`:
 
-	* filter=git-crypt diff=git-crypt
-	.gitattributes !filter !diff
-
-The second pattern is essential for ensuring that .gitattributes itself
-is not encrypted.
+	dir/** filter=git-crypt diff=git-crypt
 
 
 MAILING LISTS

README.md

@@ -153,7 +153,7 @@ encrypt all files beneath it.
 Also note that the pattern `dir/*` does not match files under
 sub-directories of dir/.  To encrypt an entire sub-tree dir/, use `dir/**`:
 
-    /dir/** filter=git-crypt diff=git-crypt
+    dir/** filter=git-crypt diff=git-crypt
 
 Mailing Lists
 -------------