ash: remove a tentative TODO, it's a wrong idea

Upstream tried it, and then reverted by:

    From: Herbert Xu <herbert@gondor.apana.org.au>
    Date: Tue, 26 May 2020 23:19:05 +1000
    parser: Fix double-backslash nl in old-style command sub

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
1 file changed