docs: update create-next-app cli documents

[Marukome0743]

What?

This PR updates the two files.

create-next-app.mdx

1. Update --import-alias option to follow up refactor(cna): refactors and small perf wins #68225.

- | `--import-alias <alias-to-configure>`   | Specify import alias to use (default "@/\*")                    |
+ | `--import-alias <prefix/*>`           | Specify import alias to use (default "@/\*")                    |

2. Add --disable-git flag which introduced at Adding a disable git flag in Create Next App #68821.

README.md

1. Update the outputs of create-next-app --help to follow up refactor(cna): refactors and small perf wins #68225.

Improving Documentation

• Run pnpm prettier-fix to fix formatting issues before opening the PR.
• Read the Docs Contribution Guide to ensure your contribution follows the docs guidelines: https://nextjs.org/docs/community/contribution-guide

[ijjk]

Allow CI Workflow Run

• approve CI run for commit: 6d7cbd1

Note: this should only be enabled once the PR is ready to go and can only be enabled by a maintainer

[ijjk]

Allow CI Workflow Run

• approve CI run for commit: f26f6c1

Note: this should only be enabled once the PR is ready to go and can only be enabled by a maintainer