[Enhancement] Resolver doc parser performance problem

[He1pa]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

compile:
https://github.com/KusionStack/konfig/blob/main/base/examples/native/nginx_deployment/nginx_deployment.k

2. What did you expect to see? (Required)

3. What did you see instead (Required)

Each fragment at the top of the figure represents once call of parser_doc_string.
This function takes estimated 60-70% of the resolver time. After removing this function, the resolver time dropped from 70ms to 14ms

4. What is your KusionStack components version? (Required)