sage --package properties: Update help

Author: Matthias Koeppe

build/sage_bootstrap/app.py

@@ -82,7 +82,7 @@ def properties(self, *package_classes, props=['path', 'version_with_patchlevel',
         """
         Show the properties of given packages
 
-        $ sage --package properties maxima
+        $ sage --package properties --format shell maxima
         path_maxima='........./build/pkgs/maxima'
         version_with_patchlevel_maxima='5.46.0'
         type_maxima='standard'

build/sage_bootstrap/cmdline.py

@@ -90,8 +90,12 @@
 EXAMPLE:
 
     $ sage --package properties maxima
-    version_maxima='5.46.0'
-    type_maxima='standard'
+    maxima:
+            path:                        /.../build/pkgs/maxima
+            version_with_patchlevel:     5.46.0
+            type:                        standard
+            source:                      normal
+            trees:                       SAGE_LOCAL
 """