Keep snippet vars definitions in a single format across all snippets and documentation.

The format is:

# var-name: value

Previously snippets used a mixture of the following formatting:

#var-name: value
#var-name : value
# var-name: value
# var-name : value

snippets/ruby-mode/definitions/am

@@ -1,4 +1,4 @@
-#name : alias_method new, old
+# name: alias_method new, old
 # key: am
 # --
 alias_method :${new_name}, :${old_name}