docs: reporting-issues.rst: fix small typos and style issues

Fix a typo and change "head over" to "scroll down", as suggested by Jon
when reviewing another patch that used the phrase the same way.

Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
Link: https://lore.kernel.org/r/fb845d2f1db6138337203bbfac419c04b5f28053.1616181657.git.linux@leemhuis.info


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