Do not append suffix to text prompt

Do not append suffix to text prompt unless
there are choices or a default value specified.

Closes #413

test/Spectre.Console.Tests/Expectations/Widgets/Prompt/Text/NoSuffix.Output.verified.txt

@@ -0,0 +1 @@
+Enter command$ Orange

test/Spectre.Console.Tests/Unit/TextPromptTests.cs

@@ -12,6 +12,20 @@ namespace Spectre.Console.Tests.Unit
     [ExpectationPath("Widgets/Prompt/Text")]
     public sealed class TextPromptTests
     {
+        [Fact]
+        public void Should_Return_Entered_Text()
+        {
+            // Given
+            var console = new TestConsole();
+            console.Input.PushTextWithEnter("Hello World");
+
+            // When
+            var result = console.Prompt(new TextPrompt<string>("Enter text:"));
+
+            // Then
+            result.ShouldBe("Hello World");
+        }
+
         [Fact]
         [Expectation("ConversionError")]
         public Task Should_Return_Validation_Error_If_Value_Cannot_Be_Converted()
@@ -218,5 +232,22 @@ namespace Spectre.Console.Tests.Unit
             // Then
             return Verifier.Verify(console.Output);
         }
+
+        [Fact]
+        [Expectation("NoSuffix")]
+        [GitHubIssue(413)]
+        public Task Should_Not_Append_Questionmark_Or_Colon_If_No_Choices_Are_Set()
+        {
+            // Given
+            var console = new TestConsole();
+            console.Input.PushTextWithEnter("Orange");
+
+            // When
+            console.Prompt(
+                new TextPrompt<string>("Enter command$"));
+
+            // Then
+            return Verifier.Verify(console.Output);
+        }
     }
 }

test/Spectre.Console.Tests/Utilities/GitHubIssueAttribute.cs

@@ -0,0 +1,18 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Spectre.Console.Tests
+{
+    public sealed class GitHubIssueAttribute : Attribute
+    {
+        public int IssueId { get; }
+
+        public GitHubIssueAttribute(int issueId)
+        {
+            IssueId = issueId;
+        }
+    }
+}