### What it does
Checks for calls to `ends_with` with possible file extensions
and suggests to use a case-insensitive approach instead.

### Why is this bad?
`ends_with` is case-sensitive and may not detect files with a valid extension.

### Example
```
fn is_rust_file(filename: &str) -> bool {
    filename.ends_with(".rs")
}
```
Use instead:
```
fn is_rust_file(filename: &str) -> bool {
    let filename = std::path::Path::new(filename);
    filename.extension()
        .map_or(false, |ext| ext.eq_ignore_ascii_case("rs"))
}
```