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/c-mode/fopen

@@ -1,4 +1,4 @@
-#name : FILE *fp = fopen(..., ...);
+# name: FILE *fp = fopen(..., ...);
 # key: fopen
 # --
 FILE *${fp} = fopen(${"file"}, "${r}");

snippets/c-mode/printf

@@ -1,6 +1,6 @@
 # -*- mode: snippet -*-
-# name : printf 
-# contributor : joaotavora
+# name: printf 
+# contributor: joaotavora
 # key: printf
 # --
 printf ("${1:%s}\\n"${1:$(if (string-match "%" text) "," "\);")