Solve 50+ cargo doc warnings (#24071)

Release Notes:

- N/A

crates/multi_buffer/src/multi_buffer.rs

@@ -266,7 +266,7 @@ impl std::fmt::Debug for ExcerptInfo {
     }
 }
 
-/// A boundary between [`Excerpt`]s in a [`MultiBuffer`]
+/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 #[derive(Debug)]
 pub struct ExcerptBoundary {
     pub prev: Option<ExcerptInfo>,
@@ -312,7 +312,7 @@ struct Excerpt {
     has_trailing_newline: bool,
 }
 
-/// A public view into an [`Excerpt`] in a [`MultiBuffer`].
+/// A public view into an `Excerpt` in a [`MultiBuffer`].
 ///
 /// Contains methods for getting the [`Buffer`] of the excerpt,
 /// as well as mapping offsets to/from buffer and multibuffer coordinates.
@@ -332,7 +332,7 @@ struct ExcerptIdMapping {
     locator: Locator,
 }
 
-/// A range of text from a single [`Buffer`], to be shown as an [`Excerpt`].
+/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 /// These ranges are relative to the buffer itself
 #[derive(Clone, Debug, Eq, PartialEq, Hash)]
 pub struct ExcerptRange<T> {