docs: ftrace: fix ambiguous sentence

The sentence looks ambiguous, rephrase it by adding ", there".

Signed-off-by: Huichun Feng <foxhoundsk.tw@gmail.com>
Signed-off-by: Ching-Chun (Jim) Huang <jserv@ccns.ncku.edu.tw>
Signed-off-by: Chun-Hung Tseng <henrybear327@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20220111052000.2675944-1-foxhoundsk.tw@gmail.com


Signed-off-by: Jonathan Corbet <corbet@lwn.net>