Make BorrowedWithFontSystem borrow FontSystem mutably

src/buffer.rs

@@ -335,7 +335,7 @@ impl Buffer {
 
     pub fn borrow_with<'a>(
         &'a mut self,
-        font_system: &'a FontSystem,
+        font_system: &'a mut FontSystem,
     ) -> BorrowedWithFontSystem<'a, Buffer> {
         BorrowedWithFontSystem {
             inner: self,

src/edit/mod.rs

@@ -81,7 +81,7 @@ pub enum Action {
 pub trait Edit {
     fn borrow_with<'a>(
         &'a mut self,
-        font_system: &'a FontSystem,
+        font_system: &'a mut FontSystem,
     ) -> BorrowedWithFontSystem<'a, Self>
     where
         Self: Sized,

src/font/system/mod.rs

@@ -15,7 +15,7 @@ pub use fontdb;
 
 pub struct BorrowedWithFontSystem<'a, T> {
     pub(crate) inner: &'a mut T,
-    pub(crate) font_system: &'a FontSystem,
+    pub(crate) font_system: &'a mut FontSystem,
 }
 
 impl<'a, T> Deref for BorrowedWithFontSystem<'a, T> {

src/shape.rs

@@ -35,7 +35,7 @@ fn shape_fallback(
     let rtl = matches!(buffer.direction(), rustybuzz::Direction::RightToLeft);
     assert_eq!(rtl, span_rtl);
 
-    let glyph_buffer = rustybuzz::shape(&font.rustybuzz(), &[], buffer);
+    let glyph_buffer = rustybuzz::shape(font.rustybuzz(), &[], buffer);
     let glyph_infos = glyph_buffer.glyph_infos();
     let glyph_positions = glyph_buffer.glyph_positions();