According to https://eigen.tuxfamily.org/dox/TopicPitfalls.html one
should just avoid using `auto` as the type of an Eigen expression.
This PR fixes most of them I could found in the project. There might be
cases that I missed, and I might update those later if I noticed.
This should prevent issues like #7741 and hopefully fix some mysterious
crashes happened inside Eigen calls.
* Calculate extrusion width %s as a function of nozzle width, not layer height
* handled more width conversions
* more missing percent handling
* even more missed percent handling
* even more more extrusion % handling
* some fixes
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Co-authored-by: SoftFever <softfeverever@gmail.com>