Fix broken links

.gitlab-ci.yml

docs/documentation/libraries.md

docs/documentation/libraries/aircraftGeometry2/index.md

docs/documentation/sizing/empennage_design/dfe.md

...documentation/sizing/landing_gear_design/design_method.md

...tation/sizing/propulsion_design/engineering_principles.md

...ntation/sizing/propulsion_design/software_architecture.md

docs/documentation/sizing/tank_design/tank_design_method.md

docs/documentation/sizing/wing_design/dfw.md

mkdocs.yml