Everywhere: Rename {Deprecated => Byte}String

This commit un-deprecates DeprecatedString, and repurposes it as a byte
string.
As the null state has already been removed, there are no other
particularly hairy blockers in repurposing this type as a byte string
(what it _really_ is).

This commit is auto-generated:
  $ xs=$(ack -l \bDeprecatedString\b\|deprecated_string AK Userland \
    Meta Ports Ladybird Tests Kernel)
  $ perl -pie 's/\bDeprecatedString\b/ByteString/g;
    s/deprecated_string/byte_string/g' $xs
  $ clang-format --style=file -i \
    $(git diff --name-only | grep \.cpp\|\.h)
  $ gn format $(git ls-files '*.gn' '*.gni')

Userland/Libraries/LibPDF/Renderer.cpp

@@ -829,7 +829,7 @@ PDFErrorOr<void> Renderer::set_graphics_state_from_dict(NonnullRefPtr<DictObject
     return {};
 }
 
-PDFErrorOr<void> Renderer::show_text(DeprecatedString const& string)
+PDFErrorOr<void> Renderer::show_text(ByteString const& string)
 {
     if (!text_state().font)
         return Error::rendering_unsupported_error("Can't draw text because an invalid font was in use");