feat: 对输入的记号流进行分析 (#4)

添加了语法分析中各个重要状态类的`ToString`方法，方便调试

Reviewed-on: PostGuard/Canon#4

.gitea/workflows/test.yaml

@@ -12,5 +12,6 @@ jobs:
               with:
                   path: ~/.nuget/packages
                   key: ${{ runner.os }}-nuget
+                  save-always: true
             - name: Run test code
               run: dotnet test