Rollup merge of #41087 - estebank:tuple-float-index, r=arielb1

Use proper span for tuple index parsed as float

Fix diagnostic suggestion from:

```rust
help: try parenthesizing the first index
  |     (1, (2, 3)).((1, (2, 3)).1).1;
```

to the correct:

```rust
help: try parenthesizing the first index
  |     ((1, (2, 3)).1).1;
```

Fix #41081.