docs: move exportPathMap to legacy-api

[JamBalaya56562]

Description

At #71812, Legacy APIs section was created.
It's useful to gather deprecated apis and add exportPathMap docs.

In addition, remove Static Export example because it's no more use exportPathMap.

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: 9527db3

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: 52704a0

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

[ijjk]

After taking another look I don't think we want to move this to that legacy APIs folder as it is easier to find under the more specific next-config section.

comment

[JamBalaya56562]

After taking another look I don't think we want to move this to that legacy APIs folder as it is easier to find under the more specific next-config section.

Thank you for a nice review!
I recreate the similar PR #72302 which doesn't move file.