Documentation: remove warning saying that "git bisect skip" may slow …

…bisection

This warning was probably useless anyway, but it is even more so now
that filtering of skipped commits is done in C and that there is a
mechanism to skip away from broken commits.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-bisect.txt

@@ -164,9 +164,8 @@ to do it for you by issuing the command:
 $ git bisect skip                 # Current version cannot be tested
 ------------
 
-But computing the commit to test may be slower afterwards and git may
-eventually not be able to tell the first bad commit among a bad commit
-and one or more skipped commits.
+But git may eventually be unable to tell the first bad commit among
+a bad commit and one or more skipped commits.
 
 You can even skip a range of commits, instead of just one commit,
 using the "'<commit1>'..'<commit2>'" notation. For example: