Remove Error::NoErrorPossible

[declanvk]

Definition:

reckoner/src/error.rs

Line 27 in 8d6e6dd

NoErrorPossible,

Uses:

• reckoner/src/error.rs

  Line 99 in 25e7907

  Error::NoErrorPossible

• reckoner/src/error.rs

  Line 63 in 25e7907

  Error::NoErrorPossible => write!(

It seems like the main purpose is to capture the core::convert::Infalliable error. Not exactly sure where the Infallible is used, probably somewhere in conversion code.

Could this be replaced with a panic!() or unreachable!() call?