Remove actions UnfoldAt and FoldAt (#28442)

`UnfoldAt` and `FoldAt` are used internally, and don't really work
when users try to trigger them, they do however appear in the command
palette and keybindings, misleading users to try using them.

Release Notes:

- Remove unused actions `UnfoldAt` and `FoldAt` (prefer `Fold` and
`Unfold`).

crates/editor/src/actions.rs

@@ -110,20 +110,6 @@ pub struct ToggleComments {
     pub ignore_indent: bool,
 }
 
-#[derive(PartialEq, Clone, Deserialize, Default, JsonSchema)]
-#[serde(deny_unknown_fields)]
-pub struct FoldAt {
-    #[serde(skip)]
-    pub buffer_row: MultiBufferRow,
-}
-
-#[derive(PartialEq, Clone, Deserialize, Default, JsonSchema)]
-#[serde(deny_unknown_fields)]
-pub struct UnfoldAt {
-    #[serde(skip)]
-    pub buffer_row: MultiBufferRow,
-}
-
 #[derive(PartialEq, Clone, Deserialize, Default, JsonSchema)]
 #[serde(deny_unknown_fields)]
 pub struct MoveUpByLines {
@@ -226,7 +212,6 @@ impl_actions!(
         ExpandExcerpts,
         ExpandExcerptsDown,
         ExpandExcerptsUp,
-        FoldAt,
         HandleInput,
         MoveDownByLines,
         MovePageDown,
@@ -244,7 +229,6 @@ impl_actions!(
         ShowCompletions,
         ToggleCodeActions,
         ToggleComments,
-        UnfoldAt,
         FoldAtLevel,
     ]
 );