Fix TODOs/FIXMEs and missing code examples

[axmmisaka]

/workspace/lf-lang.github.io/docs/reference/containerized-execution.mdx: 96
/workspace/lf-lang.github.io/docs/reference/expressions.mdx: 161
/workspace/lf-lang.github.io/docs/reference/target-language-details.mdx
/workspace/lf-lang.github.io/docs/writing-reactors/actions.mdx:101
/workspace/lf-lang.github.io/docs/writing-reactors/inputs-and-outputs.mdx:86
/workspace/lf-lang.github.io/docs/writing-reactors/multiports-and-banks.mdx:315
/workspace/lf-lang.github.io/docs/writing-reactors/preambles.mdx:444
/workspace/lf-lang.github.io/docs/writing-reactors/time-and-timers.mdx: 33. 97

rs/src/Deadline.lf

Most of them are Rusty (pun intended)