git-cherry-pick: improve description of -x.
git-cherry-pick: improve description of -x.

Reword the first sentence of the description of -x, in order to
make it easier to read and understand.

Signed-off-by: Ralf Wildenhues <6ba98f67a915e494dbaafcb2b9f59e458e697276@gmx.de>
Signed-off-by: Shawn O. Pearce <f01032651c12a22b2103346ba96b3b6b231f9d3c@spearce.org>

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