Add Span<char> Equals overloads for nullable string

Added two Equals extension method overloads to TextExtensions, enabling Span<char> and ReadOnlySpan<char> comparisons with nullable strings using StringComparison. These handle null strings safely and delegate to existing span-based logic.

Author: electricessence

Source/Extensions.Equals.cs

@@ -34,6 +34,16 @@ public static bool Equals(this Span<char> source, StringSegment other, StringCom
 		};
 	}
 
+	// Cover the edge case of string null:
+
+	/// <inheritdoc cref="Equals(ReadOnlySpan{char}, StringSegment, StringComparison)"/>
+	public static bool Equals(this Span<char> source, string? other, StringComparison comparisonType)
+		=> other is not null && source.Equals(other.AsSpan(), comparisonType);
+
+	/// <inheritdoc cref="Equals(ReadOnlySpan{char}, StringSegment, StringComparison)"/>
+	public static bool Equals(this ReadOnlySpan<char> source, string? other, StringComparison comparisonType)
+		=> other is not null && source.Equals(other.AsSpan(), comparisonType);
+
 	/// <inheritdoc cref="Equals(ReadOnlySpan{char}, StringSegment, StringComparison)"/>
 	public static bool Equals(this Span<char> source, ReadOnlySpan<char> other, StringComparison comparisonType)
 	{