outline_panel: Rename outline_panel::Open to outline_panel::OpenSelectedEntry (#28890)

Closes #27171

The `outline_panel::Open` action seems to open the outline panel, but
instead, it moves the editor's cursor to the position of the selected
entry in the outline panel. This PR renames it to
`outline_panel::OpenSelectedEntry` for better clarity.

Meanwhile, there is an existing action, `outline_panel::ToggleFocus`,
that should be used for opening the outline panel.

Todo:
- [x] Added migration

Release Notes:

- Renamed `outline_panel::Open` to `outline_panel::OpenSelectedEntry`
for better clarity.

crates/migrator/src/migrator.rs

@@ -98,6 +98,10 @@ pub fn migrate_keymap(text: &str) -> Result<Option<String>> {
             migrations::m_2025_03_06::KEYMAP_PATTERNS,
             &KEYMAP_QUERY_2025_03_06,
         ),
+        (
+            migrations::m_2025_04_15::KEYMAP_PATTERNS,
+            &KEYMAP_QUERY_2025_04_15,
+        ),
     ];
     run_migrations(text, migrations)
 }
@@ -176,6 +180,10 @@ define_query!(
     KEYMAP_QUERY_2025_03_06,
     migrations::m_2025_03_06::KEYMAP_PATTERNS
 );
+define_query!(
+    KEYMAP_QUERY_2025_04_15,
+    migrations::m_2025_04_15::KEYMAP_PATTERNS
+);
 
 // settings
 define_query!(