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/LibXML/DOM/Document.h

@@ -20,14 +20,14 @@ enum class Version {
 };
 
 struct Doctype {
-    DeprecatedString type;
+    ByteString type;
     Vector<MarkupDeclaration> markup_declarations;
     Optional<ExternalID> external_id;
 };
 
 class Document {
 public:
-    explicit Document(NonnullOwnPtr<Node> root, Optional<Doctype> doctype, HashMap<Name, DeprecatedString> processing_instructions, Version version)
+    explicit Document(NonnullOwnPtr<Node> root, Optional<Doctype> doctype, HashMap<Name, ByteString> processing_instructions, Version version)
         : m_root(move(root))
         , m_processing_instructions(move(processing_instructions))
         , m_version(version)
@@ -38,7 +38,7 @@ public:
     Node& root() { return *m_root; }
     Node const& root() const { return *m_root; }
 
-    HashMap<Name, DeprecatedString> const& processing_instructions() const { return m_processing_instructions; }
+    HashMap<Name, ByteString> const& processing_instructions() const { return m_processing_instructions; }
 
     Version version() const { return m_version; }
 
@@ -46,7 +46,7 @@ public:
 
 private:
     NonnullOwnPtr<Node> m_root;
-    HashMap<Name, DeprecatedString> m_processing_instructions;
+    HashMap<Name, ByteString> m_processing_instructions;
     Version m_version;
     Optional<Doctype> m_explicit_doctype;
 };

Userland/Libraries/LibXML/DOM/DocumentTypeDeclaration.h

@@ -6,7 +6,7 @@
 
 #pragma once
 
-#include <AK/DeprecatedString.h>
+#include <AK/ByteString.h>
 #include <AK/HashTable.h>
 #include <AK/Variant.h>
 #include <AK/Vector.h>
@@ -73,7 +73,7 @@ struct AttributeListDeclaration {
     };
     struct Enumeration {
         // FIXME: NMToken
-        HashTable<DeprecatedString> tokens;
+        HashTable<ByteString> tokens;
     };
     using Type = Variant<StringType, TokenizedType, NotationType, Enumeration>;
 
@@ -82,10 +82,10 @@ struct AttributeListDeclaration {
     struct Implied {
     };
     struct Fixed {
-        DeprecatedString value;
+        ByteString value;
     };
     struct DefaultValue {
-        DeprecatedString value;
+        ByteString value;
     };
 
     using Default = Variant<Required, Implied, Fixed, DefaultValue>;
@@ -100,11 +100,11 @@ struct AttributeListDeclaration {
 };
 
 struct PublicID {
-    DeprecatedString public_literal;
+    ByteString public_literal;
 };
 
 struct SystemID {
-    DeprecatedString system_literal;
+    ByteString system_literal;
 };
 
 struct ExternalID {
@@ -119,12 +119,12 @@ struct EntityDefinition {
 
 struct GEDeclaration {
     Name name;
-    Variant<DeprecatedString, EntityDefinition> definition;
+    Variant<ByteString, EntityDefinition> definition;
 };
 
 struct PEDeclaration {
     Name name;
-    Variant<DeprecatedString, ExternalID> definition;
+    Variant<ByteString, ExternalID> definition;
 };
 
 using EntityDeclaration = Variant<GEDeclaration, PEDeclaration>;

Userland/Libraries/LibXML/DOM/Node.h

@@ -6,7 +6,7 @@
 
 #pragma once
 
-#include <AK/DeprecatedString.h>
+#include <AK/ByteString.h>
 #include <AK/HashMap.h>
 #include <AK/Variant.h>
 #include <AK/Vector.h>
@@ -16,7 +16,7 @@ namespace XML {
 
 struct Attribute {
     Name name;
-    DeprecatedString value;
+    ByteString value;
 };
 
 struct Offset {
@@ -30,11 +30,11 @@ struct Node {
         StringBuilder builder;
     };
     struct Comment {
-        DeprecatedString text;
+        ByteString text;
     };
     struct Element {
         Name name;
-        HashMap<Name, DeprecatedString> attributes;
+        HashMap<Name, ByteString> attributes;
         Vector<NonnullOwnPtr<Node>> children;
     };