std: remove BoundedArray

This use case is handled by ArrayListUnmanaged via the "...Bounded"
method variants, and it's more optimal to share machine code, versus
generating multiple versions of each function for differing array
lengths.

lib/std/array_list.zig

@@ -657,6 +657,7 @@ pub fn ArrayListAlignedUnmanaged(comptime T: type, comptime alignment: ?mem.Alig
 
         /// Initialize with externally-managed memory. The buffer determines the
         /// capacity, and the length is set to zero.
+        ///
         /// When initialized this way, all functions that accept an Allocator
         /// argument cause illegal behavior.
         pub fn initBuffer(buffer: Slice) Self {