remove hsl from comments

src/ImageSharp/Processing/Extensions/LightnessExtension.cs

@@ -6,7 +6,7 @@ using SixLabors.Primitives;
 namespace SixLabors.ImageSharp.Processing
 {
     /// <summary>
-    /// Defines extensions that allow to change image lightness in terms of HSL.
+    /// Defines extensions that allow to change image lightness.
     /// </summary>
     public static class LightnessExtension
     {
@@ -14,7 +14,7 @@ namespace SixLabors.ImageSharp.Processing
         /// Alters the lightness parameter of the image.
         /// </summary>
         /// <param name="source">The image this method extends.</param>
-        /// <param name="lightness">Lightness parameter of image in HSL color scheme.</param>
+        /// <param name="lightness">Lightness parameter of image.</param>
         /// <returns>The <see cref="IImageProcessingContext"/> to allow chaining of operations.</returns>
         public static IImageProcessingContext Lightness(this IImageProcessingContext source, float lightness)
             => source.ApplyProcessor(new LightnessProcessor(lightness));
@@ -23,7 +23,7 @@ namespace SixLabors.ImageSharp.Processing
         /// Alters the lightness parameter of the image.
         /// </summary>
         /// <param name="source">The image this method extends.</param>
-        /// <param name="lightness">Lightness parameter of image in HSL color scheme.</param>
+        /// <param name="lightness">Lightness parameter of image.</param>
         /// <param name="rectangle">
         /// The <see cref="Rectangle"/> structure that specifies the portion of the image object to alter.
         /// </param>

src/ImageSharp/Processing/Processors/Filters/LightnessProcessor.cs

@@ -11,7 +11,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Filters
         /// <summary>
         /// Initializes a new instance of the <see cref="LightnessProcessor"/> class.
         /// </summary>
-        /// <param name="lightness">Lightness of image in HSL color scheme</param>
+        /// <param name="lightness">Lightness of image</param>
         public LightnessProcessor(float lightness)
         : base(KnownFilterMatrices.CreateLightnessFilter(lightness))
         {
@@ -19,8 +19,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Filters
         }
 
         /// <summary>
-        /// Gets Lightness of image in HSL color scheme.
-        /// The "brightness relative to the brightness of a similarly illuminated white" https://en.wikipedia.org/wiki/HSL_and_HSV#Lightness
+        /// Gets Lightness of image.
         /// </summary>
         public float Lightness { get; }
     }