feat: 前端界面优化 (#48)

Co-authored-by: jackfiled <xcrenchangjun@outlook.com>
Reviewed-on: PostGuard/Canon#48
Co-authored-by: Ichirinko <1621543655@qq.com>
Co-committed-by: Ichirinko <1621543655@qq.com>

Canon.Tests/GrammarParserTests/PascalGrammarTests.cs

@@ -84,8 +84,9 @@ public class PascalGrammarTests
     {
         const string program = """
                                program varTest;
-                               var a : char;
+                               var a : integer;
                                begin
+                               a := 9 div 1;
                                end.
                                """;