Quick fix to remove unused parameter leaves unwanted whitespace

The quick fix _Remove unused parameter_ leaves a whitespace behind, if there are further parameters.

Before:
```rust
fn foo(<|>unused: u8, used: u8) -> u8 {
  return used;
}
```

After:
```rust
fn foo( used: u8) -> u8 {
  return used;
}
```
Note the whitespace before `used`.