added a unit test for the completion suggest on the search

Author: Mpdreamz

src/Nest.Tests.Unit/Search/suggest/CompletionSuggestTests.cs

@@ -73,5 +73,36 @@ public void CompletionSuggestDescriptorFuzzyTest()
 
             Assert.IsTrue(json.JsonEquals(expected), json);
         }
+
+		[Test]
+		public void CompletionSuggestOnSearchTest()
+		{
+			var search = this._client.Search<ElasticSearchProject>(s => s
+				.SuggestCompletion("mycompletionsuggest", ts => ts
+					.Text("n")
+					.OnField(p=>p.Name)
+					.Fuzzy()
+				)
+			);
+
+			var expected = @"{
+				suggest: {
+					mycompletionsuggest: {
+						text: ""n"",
+						completion: {
+							fuzzy: {
+								edit_distance: 1,
+								transpositions: true,
+								min_length: 3,
+								prefix_length: 1
+							},
+							field: ""name""
+						}
+					}
+				}
+			}";
+			var json = search.ConnectionStatus.Request;
+			Assert.True(json.JsonEquals(expected), json);
+		}
     }
 }

src/Nest/DSL/SearchDescriptor.cs

@@ -888,6 +888,11 @@ public SearchDescriptor<T> SuggestGlobalText(string globalSuggestText)
 			return this;
 		}
 
+
+		/// <summary>
+		/// The term suggester suggests terms based on edit distance. The provided suggest text is analyzed before terms are suggested. 
+		/// The suggested terms are provided per analyzed suggest text token. The term suggester doesn’t take the query into account that is part of request.
+		/// </summary>
 		public SearchDescriptor<T> SuggestTerm(string name, Func<TermSuggestDescriptor<T>, TermSuggestDescriptor<T>> suggest)
 		{
 			name.ThrowIfNullOrEmpty("name");
@@ -901,6 +906,10 @@ public SearchDescriptor<T> SuggestTerm(string name, Func<TermSuggestDescriptor<T
 			return this;
 		}
 
+		/// <summary>
+		/// The phrase suggester adds additional logic on top of the term suggester to select entire corrected phrases 
+		/// instead of individual tokens weighted based on ngram-langugage models. 
+		/// </summary>
 		public SearchDescriptor<T> SuggestPhrase(string name, Func<PhraseSuggestDescriptor<T>, PhraseSuggestDescriptor<T>> suggest)
 		{
 			name.ThrowIfNullOrEmpty("name");
@@ -915,6 +924,10 @@ public SearchDescriptor<T> SuggestPhrase(string name, Func<PhraseSuggestDescript
 			return this;
 		}
 
+		/// <summary>
+		/// The completion suggester is a so-called prefix suggester. 
+		/// It does not do spell correction like the term or phrase suggesters but allows basic auto-complete functionality.
+		/// </summary>
 		public SearchDescriptor<T> SuggestCompletion(string name, Func<CompletionSuggestDescriptor<T>, CompletionSuggestDescriptor<T>> suggest)
 		{
 			name.ThrowIfNullOrEmpty("name");