Improve continuation detection for string literals

Author: d-alonso

src/scanner.c

@@ -389,6 +389,7 @@ static bool scan_string_literal(TSLexer *lexer) {
                     advance(lexer);
                 }
             }
+            continue;
         }
 
         // If we hit the same kind of quote that opened this literal,

test/corpus/line_continuations.txt

@@ -472,11 +472,33 @@ end program test
 
 ================================================================================
 Line continuation as part of string
-:error
 ================================================================================
 program main
   ! This should print "I like fish&chips"
   print *, "I like fish&&
     &chips"
 end program main
 --------------------------------------------------------------------------------
+
+(translation_unit
+  (program
+    (program_statement
+      (whitespace)
+      (name)
+      (end_of_statement))
+    (whitespace)
+    (comment)
+    (whitespace)
+    (print_statement
+      (whitespace)
+      (format_identifier)
+      (whitespace)
+      (output_item_list
+        (prefixed_string_literal
+          (string_literal))))
+    (end_of_statement)
+    (end_program_statement
+      (whitespace)
+      (whitespace)
+      (name)
+      (end_of_statement))))