fix: ide-assists, some generate_\* indentations

[A4-Tacks]

Fix files:

• generate_default_from_enum_variant.rs
• generate_default_from_new.rs
• generate_deref.rs
• generate_enum_is_method.rs
• generate_enum_projection_method.rs
• generate_getter_or_setter.rs
• generate_is_empty_from_len.rs
• generate_from_impl_for_enum.rs

Example:

mod foo {
    enum Foo {
        $0String(String),
    }
}

Old output:

mod foo {
    enum Foo {
        String(String),
    }

impl From<String> for Foo {
    fn from(v: String) -> Self {
        Self::String(v)
    }
}
}

Fixed output:

mod foo {
    enum Foo {
        String(String),
    }

    impl From<String> for Foo {
        fn from(v: String) -> Self {
            Self::String(v)
        }
    }
}

[A4-Tacks]

Fixed more indentation