editor: Improve rewrapping when working with comments at different indentation levels (#18146)

This PR improves the `editor::Rewrap` command when working with comments
that were not all at the same indentation level.

We now use a heuristic of finding the most common indentation level for
each line, using the deepest indent in the event of a tie.

It also removes an `.unwrap()` that would previously lead to a panic in
this case. Instead of unwrapping we now log an error to the logs and
skip rewrapping for that selection.

Release Notes:

- Improved the behavior of `editor: rewrap` when working with a
selection that contained comments at different indentation levels.

crates/language/src/buffer.rs

@@ -144,7 +144,7 @@ pub struct BufferSnapshot {
 
 /// The kind and amount of indentation in a particular line. For now,
 /// assumes that indentation is all the same character.
-#[derive(Clone, Copy, Debug, PartialEq, Eq, Default)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, Default)]
 pub struct IndentSize {
     /// The number of bytes that comprise the indentation.
     pub len: u32,
@@ -153,7 +153,7 @@ pub struct IndentSize {
 }
 
 /// A whitespace character that's used for indentation.
-#[derive(Clone, Copy, Debug, PartialEq, Eq, Default)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, Default)]
 pub enum IndentKind {
     /// An ASCII space character.
     #[default]