Fix the wrong output of `git-show v1.3.0~155^2~4` in documentation.
Fix the wrong output of `git-show v1.3.0~155^2~4` in documentation.

Texts between ~ and ~ will be subscripted during the asciidoc translation.

Signed-off-by: Guanqun Lu <25a7077fc0f87790823c167c9b6f4d9b6c5a8a52@Gmail.com>
Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git