Master - Minor README changes and Fixed XIAO SAMD21 Description.
My first Git merge attempt. Shouldn't break anything...
First commit changes order of instructions to create the variable first. That variable can then be used for relative paths on the symbol and footprint libraries. I'd also remove the sentence about being needed for 3d models since everyone sprints through anyway so less words to read.
Second commit changes the XIAO SAMD21 description as it was a copy of the RP2040.
A couple of insignificant updates to try out the whole process.
