Improve outline panel keyboard navigation (#20385)

Closes https://github.com/zed-industries/zed/issues/20187

Make outline panel more eager to open its entries:

* scroll editor to selected outline entries (before it required an extra
`"outline_panel::Open", { "change_selection": false }` action call)
* make any `Open` action call to behave like `"outline_panel::Open", {
"change_selection": true }` and remove the redundant parameter.
Now opening an entry is equal to double clicking the same entry: the
editor gets scrolled and its selection changes
* add a way to open entries the same way as excerpts are open in multi
buffers (will open the entire file, scroll and place the caret)

* additionally, fix another race issue that caused wrong entry to be
revealed after the selection change

Release Notes:

- Improved outline panel keyboard navigation

crates/editor/src/editor.rs

@@ -49,6 +49,7 @@ pub mod test;
 
 use ::git::diff::DiffHunkStatus;
 pub(crate) use actions::*;
+pub use actions::{OpenExcerpts, OpenExcerptsSplit};
 use aho_corasick::AhoCorasick;
 use anyhow::{anyhow, Context as _, Result};
 use blink_manager::BlinkManager;
@@ -12579,11 +12580,11 @@ impl Editor {
         });
     }
 
-    fn open_excerpts_in_split(&mut self, _: &OpenExcerptsSplit, cx: &mut ViewContext<Self>) {
+    pub fn open_excerpts_in_split(&mut self, _: &OpenExcerptsSplit, cx: &mut ViewContext<Self>) {
         self.open_excerpts_common(true, cx)
     }
 
-    fn open_excerpts(&mut self, _: &OpenExcerpts, cx: &mut ViewContext<Self>) {
+    pub fn open_excerpts(&mut self, _: &OpenExcerpts, cx: &mut ViewContext<Self>) {
         self.open_excerpts_common(false, cx)
     }