more safety comment futzing

src/gc-arena/src/arena.rs

@@ -285,23 +285,23 @@ impl<R: for<'a> Rootable<'a> + ?Sized> Arena<R> {
 
 // SAFETY: The Arena is Send if the projected Root type is Send. This is safe because Gc pointers
 // are Send *only* when their branding lifetime is known to be 'static. Because an Arena only allows
-// access to the internal pointers and the gc context through a generative 'gc lifetime that is
+// access to the internal pointers and the GC context through a generative 'gc lifetime that is
 // not known to be 'static within the bounds of the callback, Gc pointers are *not* Send within the
-// callback, only "at rest" when viewed from outside the arena. Because `Context` is !Sync and !
-// Send, and `Gc<'gc, T>` is unconditionally !Sync and !Send if we don't know what 'gc is, we can't
-// really get in any trouble when inside the arena callbacks, neither Gc pointers nor pointers to
-// the Context can escape the the running thread or the mutate callback.
+// callback, only "at rest" when viewed from outside the arena. Because `Context` is !Sync and
+// !Send, and `Gc<'gc, T>` is unconditionally !Sync and !Send when we don't know what 'gc is, we
+// can't really get in any trouble when inside the arena callbacks, neither Gc pointers nor pointers
+// to the Context can escape the the running thread or the mutate callback.
 //
 // Effectively, this means that you can get a Send-able arena if every type "other than
 // Gc<'gc, T>" is Send, because outside of the arena mutate call, we can know that Gc<'gc, T> is
 // *really* `Gc<'static, T>` and thus can be Send.
 //
 // The `'gc` lifetime generated by Arena callbacks is, effectively "'static and in an arena". You
-// could use the `'gc` lifetime in a different type, other than `Gc` or other `gc_arena` types,
-// that implements Send iff 'gc == 'static, and in doing so, the projection of those types would be
-// 'static and thus also possibly Send. This must be correct though, because in order for a type
-// to be 'gc without unsafety, any 'gc types it contains must have come from `gc-arena` methods and
-// actually be "'static and in an arena".
+// can use the `'gc` lifetime in different types, other than `Gc` or other `gc_arena` types, and
+// in doing so, the projection of those types would be 'static and thus also possibly Send. This
+// must be correct though, because in order for a type to be 'gc without unsafety, any 'gc types it
+// contains must have come from `gc-arena` methods and actually be "'static and in an arena", and
+// thus safe to be Send.
 unsafe impl<R: for<'a> Rootable<'a> + ?Sized> Send for Arena<R> where Root<'static, R>: Send {}
 
 /// Create a temporary arena without a root object and perform the given operation on it. No garbage