Improve JLCPCB_CORRECTION documentation

[danieljfarrell]

Prerequisites

• I have read FAQ
• I have searched existing issues (including closed ones)
• I use KiKit at least version 1.7.2 (older version are not supported)

KiKit version

1.7.2

KiCAD version (only KiCAD 8 and 9 are supported)

9.0.8

Operating system

Windows

Description

This is a suggestion for KiKit documentation when using JLCPCB_CORRECTION.

Certain things were not clear to me but eventually I got it to work with trial and error.

You add the field in the schematic.

Rotation angle is specified ANTICLOCKWISE

For example, of you want to rotate 90 degrees clockwise, you actually need to specify 270 degrees in the field:
0;0;270

Steps to Reproduce

This is a documentation suggestion.