chore: Move the errors to a variable in the parseDocumentToAst function

Author: Dobefu

internal/lsp/parse_document_to_ast.go

@@ -1,26 +1,30 @@
 package lsp
 
 import (
+	"errors"
 	"fmt"
 
 	"github.com/Dobefu/DLiteScript/internal/ast"
 	"github.com/Dobefu/DLiteScript/internal/parser"
 	"github.com/Dobefu/DLiteScript/internal/tokenizer"
 )
 
+var errFailedToTokenizeFile = errors.New("failed to tokenize file")
+var errFailedToParseFile = errors.New("failed to parse file")
+
 func parseDocumentToAst(text string) (ast.ExprNode, error) {
 	tokenizer := tokenizer.NewTokenizer(text)
 	tokens, err := tokenizer.Tokenize()
 
 	if err != nil {
-		return nil, fmt.Errorf("failed to tokenize file: %s", err.Error())
+		return nil, fmt.Errorf("%w: %w", errFailedToTokenizeFile, err)
 	}
 
 	parser := parser.NewParser(tokens)
 	ast, err := parser.Parse()
 
 	if err != nil {
-		return nil, fmt.Errorf("failed to parse file: %s", err.Error())
+		return nil, fmt.Errorf("%w: %w", errFailedToParseFile, err)
 	}
 
 	return ast, nil