Simplify /etc/spack/modules.yaml formatting.

etc/spack/modules.yaml

@@ -5,14 +5,25 @@
 # although users can override these settings in their ~/.spack/modules.yaml.
 # -------------------------------------------------------------------------
 modules:
-  prefix_inspections: {
-        bin: ['PATH'],
-        man: ['MANPATH'],
-        lib: ['LIBRARY_PATH', 'LD_LIBRARY_PATH'],
-        lib64: ['LIBRARY_PATH', 'LD_LIBRARY_PATH'],
-        include: ['CPATH'],
-        lib/pkgconfig: ['PKGCONFIG'],
-        lib64/pkgconfig: ['PKGCONFIG'],
-        '': ['CMAKE_PREFIX_PATH']
-  }
-  enable: ['tcl', 'dotkit']
+  enable:
+    - tcl
+    - dotkit
+  prefix_inspections:
+    bin:
+      - PATH
+    man:
+      - MANPATH
+    lib:
+      - LIBRARY_PATH
+      - LD_LIBRARY_PATH
+    lib64:
+      - LIBRARY_PATH
+      - LD_LIBRARY_PATH
+    include:
+      - CPATH
+    lib/pkgconfig:
+      - PKGCONFIG
+    lib64/pkgconfig:
+      - PKGCONFIG
+    '':
+      - CMAKE_PREFIX_PATH