Rollup merge of #90336 - mbartlett21:patch-4, r=Mark-Simulacrum
Rollup merge of #90336 - mbartlett21:patch-4, r=Mark-Simulacrum

Remove extra lines in examples for `Duration::try_from_secs_*`

None of the other examples have extra lines below the `#![feature(...)]` statements, so I thought it appropriate that these examples shouldn't either.

aidancully/rust,graydon/rust,graydon/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust