Repository: quarkusio/quarkus
Issue: Reactive rest client doesn't support resource locator and subresource

### Describe the bug

When I try to use resource locator with subresource an AbstractMethodError will be thrown.

### Expected behavior

Reactive rest client will support resource locators and subresources like [here](https://github.com/stuartwdouglas/quarkus/blob/4f1b3b688a6752b51daa743b5a5b10f7e805bcc7/extensions/resteasy-reactive/rest-client-reactive/deployment/src/test/java/io/quarkus/rest/client/reactive/subresource/SubResourceTest.java#L28).

### Actual behavior

AbstractMethodError will be thrown.

### How to Reproduce?

[Reproducer](https://github.com/mkonzal/quarkus-reactive-resource-locator-subresource.git)

GET service/sub/xyz

### Output of `uname -a` or `ver`

_No response_

### Output of `java -version`

openjdk version "11.0.9.1" 2020-11-04 LTS OpenJDK Runtime Environment 18.9 (build 11.0.9.1+1-LTS) OpenJDK 64-Bit Server VM 18.9 (build 11.0.9.1+1-LTS, mixed mode)

### GraalVM version (if different from Java)

N/A

### Quarkus version or git rev

2.1.1

### Build tool (ie. output of `mvnw --version` or `gradlew --version`)

Apache Maven 3.8.1 (05c21c65bdfed0f71a2f2ada8b84da59348c4c5d)

### Additional information

_No response_

Changed files:
extensions/resteasy-reactive/rest-client-reactive/deployment/src/main/java/io/quarkus/rest/client/reactive/deployment/RestClientReactiveProcessor.java
extensions/resteasy-reactive/rest-client-reactive/deployment/src/test/java/io/quarkus/rest/client/reactive/subresource/SubResourceTest.java

diff --git a/extensions/resteasy-reactive/rest-client-reactive/deployment/src/main/java/io/quarkus/rest/client/reactive/deployment/RestClientReactiveProcessor.java b/extensions/resteasy-reactive/rest-client-reactive/deployment/src/main/java/io/quarkus/rest/client/reactive/deployment/RestClientReactiveProcessor.java
index 78f3f96305a..8e1ecbdb16b 100644
--- a/extensions/resteasy-reactive/rest-client-reactive/deployment/src/main/java/io/quarkus/rest/client/reactive/deployment/RestClientReactiveProcessor.java
+++ b/extensions/resteasy-reactive/rest-client-reactive/deployment/src/main/java/io/quarkus/rest/client/reactive/deployment/RestClientReactiveProcessor.java
@@ -423,6 +423,8 @@ private boolean isRestMethod(MethodInfo method) {
             if (annotation.target().kind() == AnnotationTarget.Kind.METHOD
                     && BUILTIN_HTTP_ANNOTATIONS_TO_METHOD.containsKey(annotation.name())) {
                 return true;
+            } else if (annotation.name().equals(ResteasyReactiveDotNames.PATH)) {
+                return true;
             }
         }
         return false;
diff --git a/extensions/resteasy-reactive/rest-client-reactive/deployment/src/test/java/io/quarkus/rest/client/reactive/subresource/SubResourceTest.java b/extensions/resteasy-reactive/rest-client-reactive/deployment/src/test/java/io/quarkus/rest/client/reactive/subresource/SubResourceTest.java
index 186ccc348e9..586e096a482 100644
--- a/extensions/resteasy-reactive/rest-client-reactive/deployment/src/test/java/io/quarkus/rest/client/reactive/subresource/SubResourceTest.java
+++ b/extensions/resteasy-reactive/rest-client-reactive/deployment/src/test/java/io/quarkus/rest/client/reactive/subresource/SubResourceTest.java
@@ -17,6 +17,7 @@
 import org.eclipse.microprofile.rest.client.RestClientBuilder;
 import org.eclipse.microprofile.rest.client.annotation.ClientHeaderParam;
 import org.eclipse.microprofile.rest.client.inject.RegisterRestClient;
+import org.eclipse.microprofile.rest.client.inject.RestClient;
 import org.jboss.shrinkwrap.api.ShrinkWrap;
 import org.jboss.shrinkwrap.api.spec.JavaArchive;
 import org.junit.jupiter.api.Test;
@@ -35,6 +36,16 @@ public class SubResourceTest {
     @TestHTTPResource
     URI baseUri;
 
+    @RestClient
+    RootClient injectedClient;
+
+    @Test
+    void testInjectedClient() {
+        // should result in sending GET /path/rt/mthd/simple
+        String result = injectedClient.sub("rt", "mthd").simpleGet();
+        assertThat(result).isEqualTo("rt/mthd/simple");
+    }
+
     @Test
     void shouldPassParamsToSubResource() {
         // should result in sending GET /path/rt/mthd/simple
@@ -62,7 +73,7 @@ void shouldDoMultiplePosts() {
     }
 
     @Path("/path/{rootParam}")
-    @RegisterRestClient
+    @RegisterRestClient(baseUri = "http://localhost:8081")
     @Consumes("text/plain")
     @Produces("text/plain")
     @ClientHeaderParam(name = "fromRoot", value = "headerValue")