LibGfx: Change Emoji::emoji_for_code_points to accept const code points

Span<u32 const> is the type used when converting a constant Vector<u32>
to a Span.

Userland/Libraries/LibGfx/Font/Emoji.cpp

@@ -25,7 +25,7 @@ Bitmap const* Emoji::emoji_for_code_point(u32 code_point)
     return emoji_for_code_points(Array { code_point });
 }
 
-Bitmap const* Emoji::emoji_for_code_points(Span<u32> const& code_points)
+Bitmap const* Emoji::emoji_for_code_points(Span<u32 const> const& code_points)
 {
     // FIXME: This function is definitely not fast.
     auto basename = String::join('_', code_points, "U+{:X}"sv);

Userland/Libraries/LibGfx/Font/Emoji.h

@@ -17,7 +17,7 @@ class Bitmap;
 class Emoji {
 public:
     static Gfx::Bitmap const* emoji_for_code_point(u32 code_point);
-    static Gfx::Bitmap const* emoji_for_code_points(Span<u32> const&);
+    static Gfx::Bitmap const* emoji_for_code_points(Span<u32 const> const&);
     static Gfx::Bitmap const* emoji_for_code_point_iterator(Utf8CodePointIterator&);
 };