…ed them in "needless_bool".

Co-Authored-By: daxpedda <1645124+daxpedda@users.noreply.github.com>

Fix automatic suggestion on `use_self`.

In an example like this:
```rust
impl Example {
    fn fun_1() { }
    fn fun_2() {
        Example::fun_1();
    }
}
```
Clippy tries to replace `Example::fun_1` with `Self`, loosing `::fun_1` in the process, it should rather try to replace `Example` with `Self`.

**Question**
- There may be other paths that need the same treatment, but I'm not sure I understand them fully:
  - https://github.com/rust-lang/rust-clippy/blob/e648adf0866a1cea7db6ce2d33ea86e442f25377/clippy_lints/src/use_self.rs#L94-L96
  - https://github.com/rust-lang/rust-clippy/blob/e648adf0866a1cea7db6ce2d33ea86e442f25377/clippy_lints/src/use_self.rs#L225-L229

…lip1995

Add assert(true) and assert(false) lints

This PR add two lints on assert!(true) and assert!(false).
rust-lang#3575

…ns, r=oli-obk

"make_return" and "blockify" convenience methods, fixes rust-lang#3683

…ed them in "needless_bool".

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