LibUnicode: Update out-of-date spec links

And remove links that aren't adding much value but will often get out of
date (i.e. links to UCD files, which are already all listed in
unicode_data.cmake).

Meta/Lagom/Tools/CodeGenerators/LibUnicode/GenerateUnicodeData.cpp

@@ -30,8 +30,7 @@ struct CodePointRange {
     u32 last;
 };
 
-// SpecialCasing source: https://www.unicode.org/Public/13.0.0/ucd/SpecialCasing.txt
-// Field descriptions: https://www.unicode.org/reports/tr44/tr44-13.html#SpecialCasing.txt
+// https://www.unicode.org/reports/tr44/#SpecialCasing.txt
 struct SpecialCasing {
     u32 index { 0 };
     u32 code_point { 0 };
@@ -42,7 +41,7 @@ struct SpecialCasing {
     DeprecatedString condition;
 };
 
-// Field descriptions: https://www.unicode.org/reports/tr44/#Character_Decomposition_Mappings
+// https://www.unicode.org/reports/tr44/#Character_Decomposition_Mappings
 struct CodePointDecomposition {
     // `tag` is a string since it's used for codegen as an enum value.
     DeprecatedString tag { "Canonical"sv };
@@ -50,12 +49,10 @@ struct CodePointDecomposition {
     size_t decomposition_size { 0 };
 };
 
-// PropList source: https://www.unicode.org/Public/13.0.0/ucd/PropList.txt
-// Property descriptions: https://www.unicode.org/reports/tr44/tr44-13.html#PropList.txt
+// https://www.unicode.org/reports/tr44/#PropList.txt
 using PropList = HashMap<DeprecatedString, Vector<CodePointRange>>;
 
-// Normalization source: https://www.unicode.org/Public/13.0.0/ucd/DerivedNormalizationProps.txt
-// Normalization descriptions: https://www.unicode.org/reports/tr44/#DerivedNormalizationProps.txt
+// https://www.unicode.org/reports/tr44/#DerivedNormalizationProps.txt
 enum class QuickCheck {
     Yes,
     No,
@@ -75,9 +72,7 @@ struct CodePointName {
     size_t name { 0 };
 };
 
-// UnicodeData source: https://www.unicode.org/Public/13.0.0/ucd/UnicodeData.txt
-// Field descriptions: https://www.unicode.org/reports/tr44/tr44-13.html#UnicodeData.txt
-//                     https://www.unicode.org/reports/tr44/#General_Category_Values
+// https://www.unicode.org/reports/tr44/#UnicodeData.txt
 struct CodePointData {
     u32 code_point { 0 };
     DeprecatedString name;
@@ -128,6 +123,7 @@ struct UnicodeData {
     HashMap<u32, size_t> code_point_display_name_aliases;
     Vector<CodePointName> code_point_display_names;
 
+    // https://www.unicode.org/reports/tr44/#General_Category_Values
     PropList general_categories;
     Vector<Alias> general_category_aliases;
 

Userland/Libraries/LibUnicode/CharacterTypes.cpp

@@ -17,9 +17,6 @@
 #    include <LibUnicode/UnicodeData.h>
 #endif
 
-// For details on the algorithms used here, see Section 3.13 Default Case Algorithms
-// https://www.unicode.org/versions/Unicode13.0.0/ch03.pdf
-
 namespace Unicode {
 
 Optional<DeprecatedString> __attribute__((weak)) code_point_display_name(u32) { return {}; }

Userland/Libraries/LibUnicode/UnicodeUtils.cpp

@@ -16,7 +16,7 @@
 #endif
 
 // For details on the algorithms used here, see Section 3.13 Default Case Algorithms
-// https://www.unicode.org/versions/Unicode13.0.0/ch03.pdf
+// https://www.unicode.org/versions/Unicode15.0.0/ch03.pdf
 
 namespace Unicode::Detail {
 
@@ -197,6 +197,7 @@ static SpecialCasing const* find_matching_special_case(u32 code_point, Utf8View
 
 #endif
 
+// https://www.unicode.org/versions/Unicode15.0.0/ch03.pdf#G34078
 ErrorOr<void> build_lowercase_string([[maybe_unused]] Utf8View code_points, [[maybe_unused]] StringBuilder& builder, [[maybe_unused]] Optional<StringView> const& locale)
 {
 #if ENABLE_UNICODE_DATA
@@ -223,6 +224,7 @@ ErrorOr<void> build_lowercase_string([[maybe_unused]] Utf8View code_points, [[ma
 #endif
 }
 
+// https://www.unicode.org/versions/Unicode15.0.0/ch03.pdf#G34078
 ErrorOr<void> build_uppercase_string([[maybe_unused]] Utf8View code_points, [[maybe_unused]] StringBuilder& builder, [[maybe_unused]] Optional<StringView> const& locale)
 {
 #if ENABLE_UNICODE_DATA
@@ -249,6 +251,7 @@ ErrorOr<void> build_uppercase_string([[maybe_unused]] Utf8View code_points, [[ma
 #endif
 }
 
+// https://www.unicode.org/versions/Unicode15.0.0/ch03.pdf#G34078
 ErrorOr<void> build_titlecase_string([[maybe_unused]] Utf8View code_points, [[maybe_unused]] StringBuilder& builder, [[maybe_unused]] Optional<StringView> const& locale)
 {
 #if ENABLE_UNICODE_DATA