grammar: don't use immediate token in the escape sequence...

to fix first character in the connection path shape key

Related #21

grammar.js

@@ -419,7 +419,7 @@ module.exports = grammar({
     _unescaped_double_string_fragment: ($) => token.immediate(/[^"\\\n]+/),
 
     escape_sequence: ($) =>
-      token.immediate(
+      token(
         seq(
           "\\",
           choice(

src/grammar.json

@@ -2155,7 +2155,7 @@
       }
     },
     "escape_sequence": {
-      "type": "IMMEDIATE_TOKEN",
+      "type": "TOKEN",
       "content": {
         "type": "SEQ",
         "members": [

test/corpus/connection.txt

@@ -245,3 +245,26 @@ Connection with espaced key fragments
     )
   )
 )
+
+
+================================================================================
+Connection with espaced key fragments
+================================================================================
+\#hello\[\] -- \[world\]
+
+--------------------------------------------------------------------------------
+
+(source_file
+  (connection
+    (shape_key
+      (escape_sequence)
+      (escape_sequence)
+      (escape_sequence)
+    )
+    (arrow)
+    (shape_key
+      (escape_sequence)
+      (escape_sequence)
+    )
+  )
+)

test/corpus/shape.txt

@@ -3,6 +3,7 @@ Declare unquoted shape identifier with escape sequence (issue #21)
 ================================================================================
 hello\[world\]
 \#ello\[world\]
+\#    helloello\[world\]
 --------------------------------------------------------------------------------
 
 (source_file
@@ -19,6 +20,13 @@ hello\[world\]
       (escape_sequence)
     )
   )
+  (shape
+    (shape_key
+      (escape_sequence)
+      (escape_sequence)
+      (escape_sequence)
+    )
+  )
 )
 
 ================================================================================