cmd-index: Fix formatting
cmd-index: Fix formatting

The documentation of the `sequence show` was incorrectly
indented with spaces instead of tabs.

Change-Id: I6fc7f1da14dd1c32d539f8f56ee7e7c1657f9da6

GerritCodeReview/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit