foo_bar and fooBar types become both FooBar once generated, triggering duplicate errors

[nathani-axis]

I have a schema with this in it:

type Object {
    foo_bar: FooBar
    fooBar: FooBar
}

and when I run gqlgenc I get:

FooBar *FooBar `json:"foo_bar"`
FooBar *FooBar `json:"fooBar"`

which introduces a duplicate error. It's fixed when I manually change that code to:

Foo_Bar *FooBar `json:"foo_bar"`
FooBar  *FooBar `json:"fooBar"`