update examples

examples/full-syntax.rs

examples/generics.rs

examples/modules.rs

examples/nested.rs

examples/one-task.rs

examples/preemption.rs

examples/two-tasks.rs

examples/zero-tasks.rs

src/examples/_0_zero_tasks.rs

src/examples/_1_one_task.rs

src/examples/_2_two_tasks.rs

src/examples/_3_preemption.rs

src/examples/_4_nested.rs

src/examples/_5_generics.rs

src/examples/_6_full_syntax.rs