Make Edit::copy_selection immutable

src/edit/editor.rs

@@ -109,7 +109,7 @@ impl Edit for Editor {
         }
     }
 
-    fn copy_selection(&mut self) -> Option<String> {
+    fn copy_selection(&self) -> Option<String> {
         let select = self.select_opt?;
 
         let (start, end) = match select.line.cmp(&self.cursor.line) {

src/edit/mod.rs

@@ -115,7 +115,7 @@ pub trait Edit {
     fn shape_as_needed(&mut self, font_system: &mut FontSystem);
 
     /// Copy selection
-    fn copy_selection(&mut self) -> Option<String>;
+    fn copy_selection(&self) -> Option<String>;
 
     /// Delete selection, adjusting cursor and returning true if there was a selection
     // Also used by backspace, delete, insert, and enter when there is a selection

src/edit/syntect.rs

@@ -250,7 +250,7 @@ impl<'a> Edit for SyntaxEditor<'a> {
         self.editor.shape_as_needed(font_system);
     }
 
-    fn copy_selection(&mut self) -> Option<String> {
+    fn copy_selection(&self) -> Option<String> {
         self.editor.copy_selection()
     }
 

src/edit/vi.rs

@@ -81,7 +81,7 @@ impl<'a> Edit for ViEditor<'a> {
         self.editor.shape_as_needed(font_system);
     }
 
-    fn copy_selection(&mut self) -> Option<String> {
+    fn copy_selection(&self) -> Option<String> {
         self.editor.copy_selection()
     }