Rollup merge of #139294 - beetrees:fix-f16-f128-literal-feature-gate, r=fmease

Fix the `f16`/`f128` feature gates on integer literals

The feature gating logic for `f16`/`f128` currently only checks float literals, meaning this code currently compiles with no feature gates on stable ([playground](https://play.rust-lang.org/?version=stable&mode=debug&edition=2024&gist=b0c0e285ccb822fc7e2abc595557886b)):
```rust
fn main() {
    let a = 1f16;
    let b = 1f128;
    dbg!(a, b);
}
```
This PR fixes that.

Tracking issue: #116909

Author: matthiaskrgr