Address feedback

src/Analyzers/Core/Analyzers/DiagnosticCustomTags.cs

@@ -12,10 +12,8 @@ namespace Microsoft.CodeAnalysis.Diagnostics
 {
     internal static class DiagnosticCustomTags
     {
-        /// <summary>
-        /// it is string[] because DiagnosticDescriptor expects string[]. 
-        /// </summary>
         private static readonly string s_enforceOnBuildNeverTag = EnforceOnBuild.Never.ToCustomTag();
+
         private static readonly string[] s_microsoftCustomTags = new string[] { WellKnownDiagnosticTags.Telemetry };
         private static readonly string[] s_editAndContinueCustomTags = new string[] { WellKnownDiagnosticTags.EditAndContinue, WellKnownDiagnosticTags.Telemetry, WellKnownDiagnosticTags.NotConfigurable, s_enforceOnBuildNeverTag };
         private static readonly string[] s_unnecessaryCustomTags = new string[] { WellKnownDiagnosticTags.Unnecessary, WellKnownDiagnosticTags.Telemetry };

src/Analyzers/Core/Analyzers/EnforceOnBuild.cs

@@ -9,9 +9,28 @@ namespace Microsoft.CodeAnalysis.CodeStyle
     /// </summary>
     internal enum EnforceOnBuild
     {
+        /// <summary>
+        /// Indicates that the code style diagnostic is an IDE-only diagnostic that cannot be enforced on build.
+        /// </summary>
         Never,
+
+        /// <summary>
+        /// Indicates that the code style diagnostic can be enforced on build when explicitly enabled in a configuration file,
+        /// but is not part of the <see cref="Recommended"/> or <see cref="HighlyRecommended"/> group for build enforcement.
+        /// <para>This is the suggested <b>P3</b> bucket of code style diagnostics to enforce on build.</para>
+        /// </summary>
         WhenExplicitlyEnabled,
+
+        /// <summary>
+        /// Indicates that the code style diagnostic can be enforced on build and is part of the recommended group for build enforcement.
+        /// <para>This is the suggested <b>P2</b> bucket of code style diagnostics to enforce on build.</para>
+        /// </summary>
         Recommended,
+
+        /// <summary>
+        /// Indicates that the code style diagnostic can be enforced on build and is part of the highly recommended group for build enforcement.
+        /// <para>This is the suggested <b>P1</b> bucket of code style diagnostics to enforce on build.</para>
+        /// </summary>
         HighlyRecommended,
     }