locking: Mark sentence-ending period as such

Silence warning from "make punctcheck":

    vvv Hint: sentence ending with an uppercase needs "\@." vvv
    ./locking/locking.tex:2039:traditionally used in scheduling disk I/O.

It is needed because commit 678e6cc3c0f1 ("locking: Cite Dice et al.
for hierarchical lock") have added a sentence in the paragraph.

Fixes: 678e6cc3c0f1 ("locking: Cite Dice et al. for hierarchical lock")
Signed-off-by: Akira Yokosawa <akiyks@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
diff --git a/locking/locking.tex b/locking/locking.tex
index e4ebce5..e0e1725 100644
--- a/locking/locking.tex
+++ b/locking/locking.tex
@@ -2036,7 +2036,7 @@
 steps to avoid
 starvation~\cite{McKenney02e,radovic03hierarchical,radovic02efficient,BenJackson02,McKenney02d}.
 Many of these can be thought of as analogous to the elevator algorithms
-traditionally used in scheduling disk I/O.
+traditionally used in scheduling disk I/O\@.
 Dice et al.~discuss use of local and global locks in order to transform
 any architecture-oblivious lock into a local/global locking scheme
 that optimizes for the system's structure by providing (for example)