Use [StringSyntax(StringSyntaxAttribute.Uri, UriKind.Absolute)] when absolute URIs are expected

src/OpenIddict.Client/OpenIddictClientBuilder.cs

@@ -1158,7 +1158,8 @@ public sealed class OpenIddictClientBuilder
     /// <param name="uri">The client URI.</param>
     /// <returns>The <see cref="OpenIddictClientBuilder"/> instance.</returns>
     [EditorBrowsable(EditorBrowsableState.Advanced)]
-    public OpenIddictClientBuilder SetClientUri([StringSyntax(StringSyntaxAttribute.Uri)] string uri)
+    public OpenIddictClientBuilder SetClientUri(
+        [StringSyntax(StringSyntaxAttribute.Uri, UriKind.Absolute)] string uri)
     {
         if (string.IsNullOrEmpty(uri))
         {

src/OpenIddict.Server/OpenIddictServerBuilder.cs

@@ -1739,7 +1739,8 @@ public sealed class OpenIddictServerBuilder
     /// </summary>
     /// <param name="uri">The issuer uri.</param>
     /// <returns>The <see cref="OpenIddictServerBuilder"/> instance.</returns>
-    public OpenIddictServerBuilder SetIssuer([StringSyntax(StringSyntaxAttribute.Uri)] string uri)
+    public OpenIddictServerBuilder SetIssuer(
+        [StringSyntax(StringSyntaxAttribute.Uri, UriKind.Absolute)] string uri)
     {
         if (string.IsNullOrEmpty(uri))
         {