Remove Field.fromNumber(x) to reduce API surface area

[jasongitmail]

Given Field(x) works equally well.

[mitschabaude]

we have three similar methods, which all duplicate part of the Field() constructor

  static fromString(x: string): Field;
  static fromNumber(x: number): Field;
  static fromBigInt(x: bigint): Field;

the only things they add is to narrow down the types that are allowed as input. I'm not sure if that adds any value though, and haven't seen any of those three used in any actual code

[bkase]

Remove them on UInt* as well

[bkase]

Search the docs to make sure that these aren't referenced anywhere and fix them