Rust: Enum names not only numbers

[leighmcculloch]

What

When generating rust code for enums that when their shared prefix is removed start with a number, add a letter to the start of the enum member name.

Why

Enums that share a prefix followed by a number result in invalid Rust code being generated. Rust, like most languages, does not allow identifiers to begin with a number.

For example:

enum BinaryFuseFilterType
{
    BINARY_FUSE_FILTER_8_BIT = 0,
    BINARY_FUSE_FILTER_16_BIT = 1,
    BINARY_FUSE_FILTER_32_BIT = 2
};

Before

pub enum BinaryFuseFilterType {
  8Bit = 0,
  16Bit = 1,
  32Bit = 2,
}

After

pub enum BinaryFuseFilterType {
  B8Bit = 0,
  B16Bit = 1,
  B32Bit = 2,
}

[graydon]

Not going to pretend I speak Ruby but this looks fairly harmless