Always take initial builder on the first parser/builder [*]

[*] Fixes bug where the builder would just copy the attributes of the
previous element.

src/parser/parser_types.nim

@@ -168,6 +168,7 @@ proc applyParsersToSingle*[T](
   tokenFoldFn: (seq[ParserToken], T) -> T,
   optional = false,
   initT: T,
+  isFirst: bool,
 ): BuilderResult[T] =
   # Apply the current parsing functions and convert to text tokens wrapped in ParserResult
   let newParser = ParserResult.ok(Parser(
@@ -188,6 +189,7 @@ proc applyParsersToSingle*[T](
             newParser.unsafeGet(),
             builder.tree
             .last()
+            .filter(x => not isFirst)
             .orElse(just(initT))
             .map((x: T) => @[tokenFoldFn(newTokens, x)])
             .getOrElse(newSeq[T]())
@@ -211,7 +213,8 @@ proc applyParsersSeqToSingle*[T](
         b.parsers,
         b.tokenFoldFn,
         b.ignoreEmpty,
-        initT
+        initT,
+        isFirst = a == builderResult
       )),
       builderResult
     )