docs: fix @cypress/grep readme links

[MikeMcC399]

Additional details

In the npm/grep/README.md for the npm module @cypress/grep:

1. The Table of Contents is outdated, causing several invalid section headings / bookmarks to be displayed. These are removed from the end of the TOC:
   [✖] #videos--blog-posts → Status: 404
   [✖] #blog-posts → Status: 404
   [✖] #mit-license → Status: 404
2. #grepfilterspecs is now #pre-filter-specs-grepfilterspecs. This is corrected:
   [✖] #grepfilterspecs → Status: 404
3. The "See also" section is eliminated, since the two repos in that section are now both archived and therefore de facto unsupported, although they are not explicitly deprecated in the npm registry:
   • cypress-select-tests - archived May 2021
   • cypress-skip-test - archived Jan 2023
4. References and links to legacy cypress/integration/ are corrected to cypress/e2e
5. Support via email and tweet is removed

Steps to test

npm install markdown-link-check -g
git clone https://github.com/cypress-io/cypress
cd cypress
markdown-link-check npm/grep/README.md

How has the user experience changed?

Users viewing npm/grep/README.md will not encounter bad or outdated links.

This PR does not itself cause a new version of @cypress/grep to be released, so the npm registry README copy will continue to be outdated.

PR Tasks

• [na] Have tests been added/updated?
• [na] Has a PR for user-facing changes been opened in cypress-documentation?
• [na] Have API changes been updated in the type definitions?

[cypress-app-bot]

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