Avoid fromat! macro usage

What it does

Checks for format! macro usage.

Why is this bad?

The usage of format! is not recommended.

Example

    #[ink(message)]
    pub fn crash(&self) -> Result<(), Error> {
        Err(Error::FormatError {
            msg: (format!("{}", self.value)),
        })
    }

Use instead:

    pub enum Error {
        FormatError { msg: String },
        CrashError
    }

    #[ink(message)]
    pub fn crash(&self) -> Result<(), Error> {
        Err(Error::FormatError { msg: self.value.to_string() })
    }

Implementation

The detector's implementation can be found at this link.