push.yml: rename 3 GitHub Actions jobs for extra clarity

Author: stephengold

.github/workflows/push.yml

@@ -5,7 +5,7 @@ name: CI at GitHub
 on: [push]
 
 jobs:
-  Java17-Linux:
+  Java17-Linux64:
     if: contains(toJson(github.event.commits), '[ci skip] ') == false
     runs-on: ubuntu-24.04
     steps:
@@ -19,7 +19,7 @@ jobs:
       - run: ./gradlew :apps:HelloLibbulletjme --console=plain --stacktrace
       - run: ./gradlew :apps:HelloVehicle0 --console=plain --stacktrace
 
-  Java21-MacOS:
+  Java21-MacOSX_ARM64:
     if: contains(toJson(github.event.commits), '[ci skip] ') == false
     runs-on: macos-26
     steps:
@@ -32,7 +32,7 @@ jobs:
       - run: ./gradlew :apps:HelloLibbulletjme --console=plain --stacktrace
       - run: ./gradlew :apps:HelloVehicle0 --console=plain --stacktrace
 
-  Java25-Windows:
+  Java25-Windows64:
     if: contains(toJson(github.event.commits), '[ci skip] ') == false
     runs-on: windows-2025
     steps: