Clarifying the application of managing negative lines, this commit elucidates
how to effectively utilize the global discount setting. The inclusion of this
feature enhances user understanding and proficiency, providing insights into
the functionality of the newly introduced setting for handling negative discount
lines.
closesodoo/documentation#7001
Task: 3638605
Related: odoo/odoo#146969
Signed-off-by: Vraj Panchal (vrpa) <vrpa@odoo.com>