doc: make jenkins command copypasteable.

Sane defaults instead of placeholders.

doc/building.dox

@@ -506,16 +506,18 @@ named `PKGBUILD-android-arm` and `PKGBUILD-android-x86`, see
 
 In `package/ci/` there are `jenkins.xml` and `jenkins-gltests.xml` files
 containing job configuration, one for build and non-GL tests and the other for
-GL tests only. Setup your Jenkins server, enable the **Git** and **Text-finder**
-plugin and download the CLI application from here:
+GL tests only. Setup your Jenkins server, enable the **Git** and
+**Text-finder** plugin and download the CLI application from here (replace
+`localhost:8080` with your server name):
 
-    http://your-jenkins-server/cli
+    http://localhost:8080/cli
 
-Then add new jobs or update existing ones (replace `<command>` with `create-job`
-or `update-job`).
+Then add new jobs or update existing ones (update path to the `*.jar` file,
+replace `localhost:8080` with your server name, replace `update-job` with
+`create-job` if the job doesn't exist yet).
 
-    java -jar jenkins-cli.jar -s http://your-jenkins-server <command> Magnum < jenkins.xml
-    java -jar jenkins-cli.jar -s http://your-jenkins-server <command> Magnum-GLTests < jenkins-gltests.xml
+    java -jar ~/jenkins-cli.jar -s http://localhost:8080 update-job Magnum < package/ci/jenkins.xml
+    java -jar ~/jenkins-cli.jar -s http://localhost:8080 update-job Magnum-GLTests < package/ci/jenkins-gltests.xml
 
 Build is done using **Ninja** build system and everything possible is enabled,
 thus you need also **SDL2**, **GLUT** and **OpenAL** libraries. It expects that
@@ -532,10 +534,10 @@ update them with the commands below. See @ref building-crosscompiling for more
 information about setting up the crosscompilers and `toolchains/` submodule.
 For Emscripten you need also **Node.js** installed to run the tests.
 
-    java -jar jenkins-cli.jar -s http://your-jenkins-server <command> Magnum-MinGW-w64 < jenkins-mingw-w64.xml
-    java -jar jenkins-cli.jar -s http://your-jenkins-server <command> Magnum-Emscripten < jenkins-emscripten.xml
-    java -jar jenkins-cli.jar -s http://your-jenkins-server <command> Magnum-NaCl < jenkins-nacl.xml
-    java -jar jenkins-cli.jar -s http://your-jenkins-server <command> Magnum-Android < jenkins-android.xml
+    java -jar ~/jenkins-cli.jar -s http://localhost:8080 update-job Magnum-MinGW-w64 < package/ci/jenkins-mingw-w64.xml
+    java -jar ~/jenkins-cli.jar -s http://localhost:8080 update-job Magnum-Emscripten < package/ci/jenkins-emscripten.xml
+    java -jar ~/jenkins-cli.jar -s http://localhost:8080 update-job Magnum-NaCl < package/ci/jenkins-nacl.xml
+    java -jar ~/jenkins-cli.jar -s http://localhost:8080 update-job Magnum-Android < package/ci/jenkins-android.xml
 */
 
 }