Update lists of non-UTF files

* .gitattributes: Don't diff text files with encodings
incompatible with UTF-8.  Add some new binary file extensions,
like '.webp'.  etc/e/eterm-direct and java/emacs.keystore
are also binary.
* admin/notes/unicode: Update similarly.

admin/notes/unicode

@@ -305,6 +305,12 @@ nontrivial changes to the build process.
 
 	src/msdos.c
 
+ * iso-latin-1
+
+     This file is used to test Emacs encoding.
+
+        test/lisp/gnus/mm-decode-resources/win1252-multipart.bin
+
  * iso-2022-cn-ext
 
      This file is externally generated from leim/MISC-DIC/cangjie-table.b5
@@ -355,19 +361,27 @@ nontrivial changes to the build process.
      Some of the entries in this list are patterns, and stand for any
      files with the listed extension.
 
+	*.bmp
+	*.cur
+	*.gif
+	*.gpg
 	*.gz
 	*.icns
 	*.ico
+	*.jpg
+	*.kbx
+	*.key
 	*.pbm
 	*.pdf
+	*.pif
 	*.png
 	*.sig
+	*.tiff
+	*.webp
+	*.zip
 	etc/e/eterm-color
-	etc/package-keyring.gpg
-	msdos/emacs.pif
-	nextstep/GNUstep/Emacs.base/Resources/emacs.tiff
-	nt/icons/hand.cur
-
+	etc/e/eterm-direct
+	java/emacs.keystore
 
 This file is part of GNU Emacs.