docs: Fix function name trailing double-()s

I noticed a double-() in the deprecated.rst rendering today. Fix that
one and two others in the Documentation/ tree.

Acked-by: "Paul E. McKenney" <[email protected]> # For RCU
Signed-off-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jonathan Corbet <[email protected]>
3 files changed