Merge #11145

11145: feat: add config to use reasonable default expression instead of todo! when filling missing fields r=Veykril a=bnjjj

Use `Default::default()` in struct fields when we ask to fill it instead of putting `todo!()` for every fields

before:

```rust
pub enum Other {
    One,
    Two,
}

pub struct Test {
    text: String,
    num: usize,
    other: Other,
}

fn t_test() {
    let test = Test {<|>};
}
``` 

after: 

```rust
pub enum Other {
    One,
    Two,
}

pub struct Test {
    text: String,
    num: usize,
    other: Other,
}

fn t_test() {
    let test = Test {
        text: String::new(),
        num: 0,
        other: todo!(),
    };
}
``` 



Co-authored-by: Benjamin Coenen <5719034+bnjjj@users.noreply.github.com>
Co-authored-by: Coenen Benjamin <benjamin.coenen@hotmail.com>

crates/syntax/src/ast/make.rs

@@ -59,6 +59,28 @@ pub mod ext {
     pub fn expr_todo() -> ast::Expr {
         expr_from_text("todo!()")
     }
+    pub fn expr_ty_default(ty: &ast::Type) -> ast::Expr {
+        expr_from_text(&format!("{}::default()", ty))
+    }
+    pub fn expr_ty_new(ty: &ast::Type) -> ast::Expr {
+        expr_from_text(&format!("{}::new()", ty))
+    }
+
+    pub fn zero_number() -> ast::Expr {
+        expr_from_text("0")
+    }
+    pub fn zero_float() -> ast::Expr {
+        expr_from_text("0.0")
+    }
+    pub fn empty_str() -> ast::Expr {
+        expr_from_text(r#""""#)
+    }
+    pub fn empty_char() -> ast::Expr {
+        expr_from_text("'\x00'")
+    }
+    pub fn default_bool() -> ast::Expr {
+        expr_from_text("false")
+    }
     pub fn empty_block_expr() -> ast::BlockExpr {
         block_expr(None, None)
     }