resolving all remarks by @posborne, fixed max line length=99, fixed rust 1.2.0 error in doc-test
resolving all remarks by @posborne, fixed max line length=99, fixed rust 1.2.0 error in doc-test

Susurrus/nix,kamalmarhubi/nix-rust,nix-rust/nix,Susurrus/nix,kamalmarhubi/nix-rust,berkowski/nix,xd009642/nix,geofft/nix-rust,Susurrus/nix,asomers/nix,carllerche/nix-rust,nix-rust/nix,posborne/rust-nix,berkowski/nix,geofft/nix-rust,kamalmarhubi/nix-rust,carllerche/nix-rust,asomers/nix,MarkusJais/nix-rust,xd009642/nix,carllerche/nix-rust,MarkusJais/nix-rust,xd009642/nix,posborne/rust-nix,posborne/rust-nix,berkowski/nix,geofft/nix-rust,MarkusJais/nix-rust