Cleaner tag pretty_print

Author: kddnewton

Diff for: README.md

@@ -36,7 +36,7 @@ From the CLI:
 
 ```sh
 $ stree ast template.haml
-(root children=[(tag attributes={} value="Hello, world!")])
+(root children=[(tag name="span" value="Hello, world!")])
 ```
 
 or

Diff for: lib/syntax_tree/haml/tag.rb

@@ -233,8 +233,14 @@ def format(q)
       def pretty_print(q)
         q.group(2, "(tag", ")") do
           q.breakable
-          q.text("attributes=")
-          q.pp(node.value[:attributes])
+          q.text("name=")
+          q.pp(node.value[:name])
+
+          if node.value[:attributes].any?
+            q.breakable
+            q.text("attributes=")
+            q.pp(node.value[:attributes])
+          end
 
           if node.value[:dynamic_attributes].new
             q.breakable