Fix bad method links in docstrings (#13471)

# Description

Seems like I developed a bit of a bad habit of trying to link

```rust
/// [`.foo()`]
```

in docstrings, and this just doesn't work automatically; you have to do 

```rust
/// [`.foo()`](Self::foo)
```

if you want it to actually link. I think I found and replaced all of
these.

# User-Facing Changes

Just docs.

crates/nu-protocol/src/errors/labeled_error.rs

@@ -37,7 +37,8 @@ pub struct LabeledError {
 impl LabeledError {
     /// Create a new plain [`LabeledError`] with the given message.
     ///
-    /// This is usually used builder-style with methods like [`.with_label()`] to build an error.
+    /// This is usually used builder-style with methods like [`.with_label()`](Self::with_label) to
+    /// build an error.
     ///
     /// # Example
     ///