Update documentation for PreScan

Author: viceroypenguin

Docs/SuperLinq.Docs/apidoc/SuperLinq.SuperEnumerable.PreScan.md

@@ -0,0 +1,6 @@
+---
+uid: SuperLinq.SuperEnumerable.PreScan``1(System.Collections.Generic.IEnumerable{``0},System.Func{``0,``0,``0},``0)
+example: [*content]
+---
+The following code example demonstrates how to perform an exclusive pre-fix scan on a sequence using `PreScan`.
+[!code-csharp[](SuperLinq/PreScan/PreScan1.linq#L6-)]

Docs/SuperLinq.Docs/apidoc/SuperLinq/PreScan/PreScan.linq

@@ -0,0 +1,17 @@
+<Query Kind="Statements">
+  <NuGetReference>SuperLinq</NuGetReference>
+  <Namespace>SuperLinq</Namespace>
+</Query>
+
+var sequence = Enumerable.Range(1, 4);
+
+// execute a scan of the sequence, returning the aggregation before processing the element
+var result = sequence.PreScan((a, b) => a + b, 0);
+
+Console.WriteLine(
+	"[" +
+	string.Join(", ", result) +
+	"]");
+
+// This code produces the following output:
+// [0, 1, 3, 6]

Source/SuperLinq/PreScan.cs

@@ -5,40 +5,38 @@ namespace SuperLinq;
 public static partial class SuperEnumerable
 {
 	/// <summary>
-	/// Performs a pre-scan (exclusive prefix sum) on a sequence of elements.
+	///	    Performs a pre-scan (exclusive prefix sum) on a sequence of elements.
 	/// </summary>
+	/// <typeparam name="TSource">
+	///	    Type of elements in source sequence
+	/// </typeparam>
+	/// <param name="source">
+	///	    Source sequence
+	/// </param>
+	/// <param name="transformation">
+	///	    An accumulator function to be invoked on each element.
+	/// </param>
+	/// <param name="identity">
+	///	    The initial accumulator value.
+	/// </param>
+	/// <exception cref="ArgumentNullException">
+	///	    <paramref name="source"/> or <paramref name="transformation"/> is <see langword="null"/>.
+	/// </exception>
+	/// <returns>
+	///	    The scanned sequence
+	/// </returns>
 	/// <remarks>
 	/// <para>
-	/// An exclusive prefix sum returns an equal-length sequence where the
-	/// N-th element is the sum of the first N-1 input elements (the first
-	/// element is a special case, it is set to the identity). More
-	/// generally, the pre-scan allows any commutative binary operation,
-	/// not just a sum.
+	///	    An exclusive prefix scan returns an equal-length sequence where the N-th element is the aggregation of the
+	///     first N-1 input elements, where the first element is simply the <paramref name="identity"/> value.
 	/// </para>
 	/// <para>
-	/// The inclusive version of PreScan is <see cref="ScanEx{TSource}"/>.
+	///	    The inclusive version of PreScan is <see cref="Scan{TSource}"/>.
 	/// </para>
 	/// <para>
-	/// This operator uses deferred execution and streams its result.
+	///	    This operator uses deferred execution and streams its result.
 	/// </para>
-	/// <example>
-	/// <code><![CDATA[
-	/// int[] values = { 1, 2, 3, 4 };
-	/// var prescan = values.PreScan((a, b) => a + b, 0);
-	/// var scan = values.Scan((a, b) => a + b);
-	/// ]]></code>
-	/// <c>prescan</c> will yield <c>{ 0, 1, 3, 6 }</c>, while <c>scan</c>
-	/// will yield <c>{ 1, 3, 6, 10 }</c>. This shows the relationship 
-	/// between the inclusive and exclusive prefix sum.
-	/// </example>
 	/// </remarks>
-	/// <typeparam name="TSource">Type of elements in source sequence</typeparam>
-	/// <param name="source">Source sequence</param>
-	/// <param name="transformation">Transformation operation</param>
-	/// <param name="identity">Identity element (see remarks)</param>
-	/// <returns>The scanned sequence</returns>
-	/// <exception cref="ArgumentNullException"><paramref name="source"/> is null</exception>
-	/// <exception cref="ArgumentNullException"><paramref name="transformation"/> is null</exception>
 	public static IEnumerable<TSource> PreScan<TSource>(
 		this IEnumerable<TSource> source,
 		Func<TSource, TSource, TSource> transformation,