Fix undefined: linkedliststack package issue

[toshko07]

• File(s) Modified: articles/binary-tree-diameter.md, articles/minimum-stack.md, articles/trapping-rain-water.md, articles/validate-parentheses.md

  • Language(s) Used: go
  • Submission URL: https://neetcode.io/problems/validate-parentheses/solution

  Summary

  Adds the missing import "github.com/a234567894/gods/stacks/linkedliststack" statement to Go code blocks in 4 article files where the linkedliststack package was used but not imported, causing an
  undefined: linkedliststack error.

  Files changed

  • articles/validate-parentheses.md
  • articles/minimum-stack.md
  • articles/trapping-rain-water.md
  • articles/binary-tree-diameter.md