Add support for space-separated env instruction

corpus/env.txt

@@ -80,3 +80,17 @@ ENV TEST2="bar"
 		(env_pair
 			name: (unquoted_string)
 			value: (double_quoted_string))))
+
+==================
+Space syntax
+==================
+
+ENV TEST1 foo
+
+---
+
+(source_file
+	(env_instruction
+		(env_pair
+			name: (unquoted_string)
+			value: (unquoted_string))))

grammar.js

@@ -70,7 +70,10 @@ module.exports = grammar({
 				env_instruction: $ => seq(
 						alias(/[eE][nN][vV]/, "ENV"),
 						$._non_newline_whitespace,
-						repeat1($.env_pair),
+						choice(
+							repeat1($.env_pair),
+							alias($._spaced_env_pair, $.env_pair),
+						)
 				),
 
 				add_instruction: $ => seq(
@@ -212,6 +215,15 @@ module.exports = grammar({
 					)),
 				),
 
+				_spaced_env_pair: $ => seq(
+					field("name", alias(/[a-zA-Z][a-zA-Z0-9_]+[a-zA-Z0-9]/, $.unquoted_string)),
+					token.immediate(/\s+/),
+					field("value", choice(
+						$.double_quoted_string,
+						$.unquoted_string,
+					)),
+				),
+
 				expose_port: $ => choice(
 					seq(
 						/\d+/,

src/grammar.json

@@ -283,11 +283,25 @@
           "name": "_non_newline_whitespace"
         },
         {
-          "type": "REPEAT1",
-          "content": {
-            "type": "SYMBOL",
-            "name": "env_pair"
-          }
+          "type": "CHOICE",
+          "members": [
+            {
+              "type": "REPEAT1",
+              "content": {
+                "type": "SYMBOL",
+                "name": "env_pair"
+              }
+            },
+            {
+              "type": "ALIAS",
+              "content": {
+                "type": "SYMBOL",
+                "name": "_spaced_env_pair"
+              },
+              "named": true,
+              "value": "env_pair"
+            }
+          ]
         }
       ]
     },
@@ -882,6 +896,48 @@
         }
       ]
     },
+    "_spaced_env_pair": {
+      "type": "SEQ",
+      "members": [
+        {
+          "type": "FIELD",
+          "name": "name",
+          "content": {
+            "type": "ALIAS",
+            "content": {
+              "type": "PATTERN",
+              "value": "[a-zA-Z][a-zA-Z0-9_]+[a-zA-Z0-9]"
+            },
+            "named": true,
+            "value": "unquoted_string"
+          }
+        },
+        {
+          "type": "IMMEDIATE_TOKEN",
+          "content": {
+            "type": "PATTERN",
+            "value": "\\s+"
+          }
+        },
+        {
+          "type": "FIELD",
+          "name": "value",
+          "content": {
+            "type": "CHOICE",
+            "members": [
+              {
+                "type": "SYMBOL",
+                "name": "double_quoted_string"
+              },
+              {
+                "type": "SYMBOL",
+                "name": "unquoted_string"
+              }
+            ]
+          }
+        }
+      ]
+    },
     "expose_port": {
       "type": "CHOICE",
       "members": [