fix(headline): be more flexible

Fix #4

Author: vigoux

corpus/headline.txt

@@ -16,3 +16,15 @@ Text
       (word)))
   (line
     (word)))
+
+
+=====================
+Headline with tag at the start
+=====================
+
+==============================================================================
+*03.1*	Word movement
+
+Text
+
+---------------

grammar.js

@@ -19,7 +19,7 @@ module.exports = grammar({
       seq(
         field('delimiter', choice(/===.*===/, /---.*---/)),
         '\n',
-        seq(repeat1($.word), $.tag),
+        repeat1($._atom),
         '\n',
       ),
 

src/grammar.json

@@ -54,20 +54,11 @@
           "value": "\n"
         },
         {
-          "type": "SEQ",
-          "members": [
-            {
-              "type": "REPEAT1",
-              "content": {
-                "type": "SYMBOL",
-                "name": "word"
-              }
-            },
-            {
-              "type": "SYMBOL",
-              "name": "tag"
-            }
-          ]
+          "type": "REPEAT1",
+          "content": {
+            "type": "SYMBOL",
+            "name": "_atom"
+          }
         },
         {
           "type": "STRING",

src/node-types.json

@@ -69,6 +69,22 @@
       "multiple": true,
       "required": true,
       "types": [
+        {
+          "type": "argument",
+          "named": true
+        },
+        {
+          "type": "backtick",
+          "named": true
+        },
+        {
+          "type": "hotlink",
+          "named": true
+        },
+        {
+          "type": "option",
+          "named": true
+        },
         {
           "type": "tag",
           "named": true