refactor: move completion replacement logic to editor

src/tui/editor.zig

@@ -6408,6 +6408,10 @@ pub const Editor = struct {
         self.completion_is_complete = is_incomplete;
     }
 
+    pub fn get_completion_replacement_selection(self: *Self, replace: Selection) ?Selection {
+        return replace.from_pos(self.buf_root() catch return null, self.metrics);
+    }
+
     pub fn select(self: *Self, ctx: Context) Result {
         var sel: Selection = .{};
         if (!try ctx.args.match(.{ tp.extract(&sel.begin.row), tp.extract(&sel.begin.col), tp.extract(&sel.end.row), tp.extract(&sel.end.col) }))

src/tui/mode/overlay/completion_dropdown.zig

@@ -276,7 +276,7 @@ fn get_replace_selection(replace: Buffer.Selection) ?Buffer.Selection {
     return if (replace.empty())
         null
     else if (tui.get_active_editor()) |edt|
-        replace.from_pos(edt.buf_root() catch return null, edt.metrics)
+        edt.get_completion_replacement_selection(replace)
     else
         replace;
 }

src/tui/mode/overlay/completion_palette.zig

@@ -205,7 +205,7 @@ fn get_replace_selection(replace: Buffer.Selection) ?Buffer.Selection {
     return if (replace.empty())
         null
     else if (tui.get_active_editor()) |edt|
-        replace.from_pos(edt.buf_root() catch return null, edt.metrics)
+        edt.get_completion_replacement_selection(replace)
     else
         replace;
 }