Document OpenFeign Querydsl usage.

Signed-off-by: Lidoca <32785562+Lidoca@users.noreply.github.com>

Closes #3859

Author: Lidoca

src/main/antora/modules/ROOT/pages/repositories/core-extensions.adoc

@@ -80,6 +80,99 @@ dependencies {
 ====
 ======
 
+Or if you use an OpenFeign fork:
+
+[tabs]
+======
+Maven::
++
+[source,xml,indent=0,subs="verbatim,quotes",role="primary"]
+----
+<dependencies>
+    <dependency>
+        <groupId>io.github.openfeign.querydsl</groupId>
+        <artifactId>querydsl-jpa</artifactId>
+        <version>${querydslVersion}</version>
+    </dependency>
+</dependencies>
+
+<build>
+    <plugins>
+        <plugin>
+            <groupId>org.apache.maven.plugins</groupId>
+            <artifactId>maven-compiler-plugin</artifactId>
+            <configuration>
+                <annotationProcessorPaths>
+                    <!-- Explicit opt-in required via annotationProcessors or
+                            annotationProcessorPaths on Java 22+, see https://bugs.openjdk.org/browse/JDK-8306819 -->
+                    <annotationProcessorPath>
+                        <groupId>io.github.openfeign.querydsl</groupId>
+                        <artifactId>querydsl-apt</artifactId>
+                        <version>${querydslVersion}</version>
+                        <classifier>jpa</classifier>
+                    </annotationProcessorPath>
+                    <annotationProcessorPath>
+                        <groupId>jakarta.persistence</groupId>
+                        <artifactId>jakarta.persistence-api</artifactId>
+                    </annotationProcessorPath>
+                </annotationProcessorPaths>
+            </configuration>
+        </plugin>
+    
+        <!-- Recommended: Some IDE's might require this configuration to include generated sources for IDE usage -->
+        <plugin>
+            <groupId>org.codehaus.mojo</groupId>
+            <artifactId>build-helper-maven-plugin</artifactId>
+            <version>3.6.0</version>
+            <executions>
+                <execution>
+                    <id>add-source</id>
+                    <phase>generate-sources</phase>
+                    <goals>
+                        <goal>add-source</goal>
+                    </goals>
+                    <configuration>
+                        <sources>
+                            <source>target/generated-sources</source>
+                        </sources>
+                    </configuration>
+                </execution>
+                <execution>
+                    <id>add-test-source</id>
+                    <phase>generate-test-sources</phase>
+                    <goals>
+                        <goal>add-test-source</goal>
+                    </goals>
+                    <configuration>
+                        <sources>
+                            <source>target/generated-test-sources</source>
+                        </sources>
+                    </configuration>
+                </execution>
+            </executions>
+        </plugin>
+    </plugins>
+</build>
+----
+
+Gradle::
++
+====
+[source,groovy,indent=0,subs="verbatim,quotes",role="secondary"]
+----
+dependencies {
+
+    implementation "io.github.openfeign.querydsl:querydsl-jpa:${querydslVersion}"
+    annotationProcessor "io.github.openfeign.querydsl:querydsl-apt:${querydslVersion}:jpa"
+    annotationProcessor 'jakarta.persistence:jakarta.persistence-api'
+
+    testAnnotationProcessor "io.github.openfeign.querydsl:querydsl-apt:${querydslVersion}:jpa"
+    testAnnotationProcessor 'jakarta.persistence:jakarta.persistence-api'
+}
+----
+====
+======
+
 Note that the setup above shows the simplemost usage omitting any other options or dependencies that your project might require.
 
 include::{commons}@data-commons::page$repositories/core-extensions-web.adoc[leveloffset=1]