diff-index.txt: update raw output format in examples

diff-index.txt: update raw output format in examples

The two examples in the doc for 'git diff-index' were not updated when
the raw output format was changed in 81e50eabf0 ([PATCH] The diff-raw
format updates., 2005-05-21) (first example) and in b6d8f309d9 ([PATCH]
diff-raw format update take #2., 2005-05-23) and 7cb6ac1e4b (diff:
diff_aligned_abbrev: remove ellipsis after abbreviated SHA-1 value,
2017-12-03) (second example).

Update the output, inventing some characters to complete the source
hash in the second example. Also correct the destination mode in the
second example, which was wrongly '100664' since the addition of the
example in c64b9b8860 (Reference documentation for the core git
commands., 2005-05-05).

Signed-off-by: Philippe Blain <levraiphilippeblain@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>