fix docs, misc tweaks

src/containers/brightness_grid.rs

@@ -1,7 +1,6 @@
-use crate::macros::wrap_functions;
 use crate::{
     containers::ByteSlice,
-    macros::{wrap_clone, wrap_free, wrap_methods},
+    macros::{wrap_clone, wrap_free, wrap_functions, wrap_methods},
     mem::{heap_move_nonnull, heap_move_ok, heap_move_some, heap_remove},
 };
 use servicepoint::{
@@ -121,11 +120,13 @@ wrap_methods!(
     ///
     /// The returned memory is valid for the lifetime of the grid.
     mut fn data_ref_mut() -> ByteSlice {
-        return(br_slice) { unsafe {
+        return(br_slice) {
             //noinspection RsAssertEqual
             const _: () = assert!(size_of::<Brightness>() == 1);
 
-            ByteSlice::from_slice(transmute::<&mut [Brightness], &mut [u8]>(br_slice))
-        }};
+            unsafe {
+                ByteSlice::from_slice(transmute::<&mut [Brightness], &mut [u8]>(br_slice))
+            }
+        };
     };
 );

src/containers/byte_slice.rs

@@ -26,7 +26,8 @@ pub struct ByteSlice {
 }
 
 impl ByteSlice {
-    pub(crate) const INVALID: ByteSlice = ByteSlice {
+    /// Represents an invalid [ByteSlice] instance.
+    pub const INVALID: ByteSlice = ByteSlice {
         start: std::ptr::null_mut(),
         length: 0,
     };

src/containers/mod.rs

@@ -11,3 +11,8 @@ pub use brightness_grid::*;
 pub use byte_slice::*;
 pub use char_grid::*;
 pub use cp437_grid::*;
+
+mod _hidden {
+    /// This is a type only used by cbindgen to have a type for pointers.
+    pub struct DisplayBitVec;
+}