fix: correct z_srvcli example feature flag syntax

Author: YuanYuYuan

.github/workflows/ci.yml

@@ -136,7 +136,7 @@ jobs:
           nix develop '.#${{ matrix.distro }}-ci' -c cargo build --example twist_pub
           nix develop '.#${{ matrix.distro }}-ci' -c cargo build --example battery_state_sub
           nix develop '.#${{ matrix.distro }}-ci' -c cargo build --example laser_scan
-          nix develop '.#${{ matrix.distro }}-ci' -c cargo build --example z_srvcli --features ros-z-msgs/external_msgs
+          nix develop '.#${{ matrix.distro }}-ci' -c cargo build --example z_srvcli --features external_msgs
 
       - name: Build protobuf demo
         run: |

README.md

@@ -81,7 +81,7 @@ cargo build -p rcl-z
 cargo build -p ros-z-msgs --features external_msgs
 
 # Build example that uses external messages (requires ROS 2)
-cargo build --example z_srvcli --features ros-z/external_msgs
+cargo build --example z_srvcli --features external_msgs
 ```
 
 ### Using Nix (Optional)
@@ -156,7 +156,7 @@ Examples are categorized by their dependencies:
 
 - **External messages** (requires ROS 2 installation):
   - `z_srvcli` - Service client/server using example_interfaces
-    - Build with: `cargo build --example z_srvcli --features ros-z/external_msgs`
+    - Build with: `cargo build --example z_srvcli --features external_msgs`
 
 - **Advanced** (requires protobuf feature):
   - `protobuf_demo` - Demonstrates protobuf serialization with both ROS