Choose your own font and size (#1154)

* Refactor text layout: don't need &Fonts in all functions
* Replace indexing in Fonts with member function
* Wrap Fonts in a Mutex
* Remove mutex for Font::glyph_info_cache
* Remove RwLock around Font::characters
* Put FontsImpl and GalleyCache behind the same Mutex
* Round font sizes to whole pixels before deduplicating them
* Make TextStyle !Copy
* Implement user-named TextStyle:s
* round font size earlier
* Cache fonts based on family and size
* Move TextStyle into egui and Style
* Remove body_text_style
* Query graphics about max texture size and use that as font atlas size
* Recreate texture atlas when it is getting full

epi/src/lib.rs

@@ -285,7 +285,7 @@ impl Frame {
         Self(Arc::new(Mutex::new(frame_data)))
     }
 
-    /// Convenience to access the underlying `backend::FrameData`.
+    /// Access the underlying [`backend::FrameData`].
     #[doc(hidden)]
     #[inline]
     pub fn lock(&self) -> std::sync::MutexGuard<'_, backend::FrameData> {