ruff: enable and fix G, RUF, UP rules

examples/multiple-meshes.py

examples/simple-dg.py

meshmode/array_context.py

meshmode/discretization/connection/__init__.py

meshmode/discretization/connection/direct.py

meshmode/discretization/connection/face.py

meshmode/discretization/connection/opposite_face.py

meshmode/discretization/poly_element.py

meshmode/discretization/visualization.py

meshmode/dof_array.py

meshmode/interop/firedrake/__init__.py

meshmode/interop/firedrake/connection.py

meshmode/interop/firedrake/mesh.py

meshmode/interop/firedrake/reference_cell.py

meshmode/interop/nodal_dg.py

meshmode/mesh/__init__.py

meshmode/mesh/generation.py

meshmode/mesh/io.py

meshmode/mesh/processing.py

meshmode/mesh/tools.py