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/LibWeb/SVG/SVGScriptElement.cpp

@@ -59,7 +59,7 @@ void SVGScriptElement::process_the_script_element()
     auto& settings_object = document().relevant_settings_object();
     auto base_url = document().base_url();
 
-    m_script = HTML::ClassicScript::create(m_document->url().to_deprecated_string(), inline_script, settings_object, base_url, m_source_line_number);
+    m_script = HTML::ClassicScript::create(m_document->url().to_byte_string(), inline_script, settings_object, base_url, m_source_line_number);
     (void)m_script->run();
 }
 

Userland/Libraries/LibWeb/SVG/SVGTextContentElement.cpp

@@ -45,9 +45,9 @@ Optional<TextAnchor> SVGTextContentElement::text_anchor() const
     }
 }
 
-DeprecatedString SVGTextContentElement::text_contents() const
+ByteString SVGTextContentElement::text_contents() const
 {
-    return child_text_content().to_deprecated_string().trim_whitespace();
+    return child_text_content().to_byte_string().trim_whitespace();
 }
 
 // https://svgwg.org/svg2-draft/text.html#__svg__SVGTextContentElement__getNumberOfChars

Userland/Libraries/LibWeb/SVG/SVGTextContentElement.h

@@ -21,7 +21,7 @@ public:
 
     Optional<TextAnchor> text_anchor() const;
 
-    DeprecatedString text_contents() const;
+    ByteString text_contents() const;
 
 protected:
     SVGTextContentElement(DOM::Document&, DOM::QualifiedName);

Userland/Libraries/LibWeb/SVG/SVGTitleElement.cpp

@@ -40,7 +40,7 @@ void SVGTitleElement::children_changed()
     auto* document_element = document().document_element();
 
     if (document_element == parent() && is<SVGElement>(document_element))
-        page.client().page_did_change_title(document().title().to_deprecated_string());
+        page.client().page_did_change_title(document().title().to_byte_string());
 }
 
 }

Userland/Libraries/LibWeb/SVG/SVGUseElement.cpp

@@ -58,13 +58,13 @@ void SVGUseElement::attribute_changed(FlyString const& name, Optional<String> co
         m_y = AttributeParser::parse_coordinate(value.value_or(String {}));
     } else if (name == SVG::AttributeNames::href) {
         // FIXME: Support the xlink:href attribute as a fallback
-        m_referenced_id = parse_id_from_href(value.value_or(String {}).to_deprecated_string());
+        m_referenced_id = parse_id_from_href(value.value_or(String {}).to_byte_string());
 
         clone_element_tree_as_our_shadow_tree(referenced_element());
     }
 }
 
-Optional<FlyString> SVGUseElement::parse_id_from_href(DeprecatedString const& href)
+Optional<FlyString> SVGUseElement::parse_id_from_href(ByteString const& href)
 {
     auto id_seperator = href.find('#');
     if (!id_seperator.has_value()) {

Userland/Libraries/LibWeb/SVG/SVGUseElement.h

@@ -48,7 +48,7 @@ private:
 
     virtual JS::GCPtr<Layout::Node> create_layout_node(NonnullRefPtr<CSS::StyleProperties>) override;
 
-    Optional<FlyString> parse_id_from_href(DeprecatedString const& href);
+    Optional<FlyString> parse_id_from_href(ByteString const& href);
 
     JS::GCPtr<DOM::Element> referenced_element();