refactor arguments display

[nlordell]

This PR refactors arguments::display_* to do a little more than just display the arguments. When implementing additional arguments flags for other PRs, I found the pattern required to use those helper methods quite tedious and error-prone (I would forget the writeln at the end, use writeln instead of write for the name, place another field between the display_* and writeln!(f) to name a few):

write!(f, "some_flag: ")?;
display_X(&f.some_flag, f)?;
writeln!(f)?;

Since the arguments::display_* methods are only ever used for fields, I thought it made sense to specialize them so its a bit more ergonomic to use:

display_X(f, "some_flag", &f.some_flag)?;

Test Plan

Run the crates and see the formatted arguments still work (not included here as it would make the PR description too long).

Some highlights:

Before:

...
balancer_sor_url: price_estimation_rate_limiter: None
...
disabled_one_inch_protocols: ["PMM1"]
...
flashbots_api_url: [https://rpc.flashbots.net/, ]
...
additional_tip_percentage: 0.05
...
solver_account: Some(PrivateKey(PrivateKey(0x1111111111111111111111111111111111111111)))
...
external_solvers: Some([ExternalSolverArg { name: "example", url: Url { scheme: "https", cannot_be_a_base: false, username: "", password: None, host: Some(Domain("example.com")), port: None, path: "/", query: None, fragment: None }, account: Address(0x1111111111111111111111111111111111111111) }
...

After:

...

balancer_sor_url: None
price_estimation_rate_limiter: None
...
disabled_one_inch_protocols: [PMM1]
...
flashbots_api_url: [https://rpc.flashbots.net/]
...
additional_tip_percentage: 0.05%
...
solver_account: PrivateKey(0x1111111111111111111111111111111111111111)
...
external_solvers: [example|https://example.com/|Address(0x1111111111111111111111111111111111111111)]
...