Fix character literal

Previously the character literal was updated
mimicking that of Rust apparently,
but Scala doesn't have curly braces in the character literal.

We do, however, support two 'u' characters.

Author: eed3si9n

corpus/literals.txt

@@ -228,6 +228,8 @@ val myChar = 'c'
 
 val otherChar = '\u0041'
 
+val otherChar2 = '\uu0041'
+
 val anotherChar = '\n'
 
 def foo(a: Char = 'c') = a + 'd'
@@ -244,6 +246,9 @@ def foo(a: Char = 'c') = a + 'd'
   (val_definition
     (identifier)
     (character_literal))
+  (val_definition
+    (identifier)
+    (character_literal))
   (function_definition
     (identifier)
     (parameters

grammar.js

@@ -1554,8 +1554,7 @@ module.exports = grammar({
                 "\\",
                 choice(
                   /[^xu]/,
-                  /u[0-9a-fA-F]{4}/,
-                  /u{[0-9a-fA-F]+}/,
+                  /uu?[0-9a-fA-F]{4}/,
                   /x[0-9a-fA-F]{2}/,
                 ),
               ),