The intel manual knows "short jumps", "near jumps" and "far jumps",
where our Label::kNear corresponds to short jumps and Label::kFar
corresponds to near jumps.
Add some words to document this.

R=mstarzinger@chromium.org

Change-Id: I2b41cc770ee2c1fecff5e7363cede264ca3cd033
Reviewed-on: https://chromium-review.googlesource.com/824270Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50075}