Update 12.temporary_ins/10.electrostatics-vacuum/25.effects-stationary-electric-field/30.parallel-1/cheatsheet.fr.md

Update 12.temporary_ins/95.electromagnetism-in-media/10.propagation-lhi-media/10.main/textbook.fr.md

Update 12.temporary_ins/95.electromagnetism-in-media/10.propagation-lhi-media/10.main/textbook.fr.md

Update 12.temporary_ins/05.coordinates-systems/30.cylindrical-coordinates/20.overview/cheatsheet.fr.md

Update 12.temporary_ins/05.coordinates-systems/30.cylindrical-coordinates/20.overview/cheatsheet.fr.md