Updates needed to english replacements in curation.py when uptream

[ivanistheone]

When KA adds new content for channels that use the manual tree replacement logic, the replacement instructions in curation.py will need to be manually updated.

For example, running /graphql.py --lang en today shows the following new subtree was added:

    {"slug": "get-ready-courses", "translatedTitle": "Math: Get ready courses", "children": [
        {"slug": "get-ready-for-3rd-grade", "translatedTitle": "Get ready for 3rd grade"},
        {"slug": "get-ready-for-4th-grade", "translatedTitle": "Get ready for 4th grade"},
        {"slug": "get-ready-for-5th-grade", "translatedTitle": "Get ready for 5th grade"},
        {"slug": "get-ready-for-6th-grade", "translatedTitle": "Get ready for 6th grade"},
        {"slug": "get-ready-for-7th-grade", "translatedTitle": "Get ready for 7th grade"},
        {"slug": "get-ready-for-8th-grade", "translatedTitle": "Get ready for 8th grade"},
        {"slug": "get-ready-for-algebra-i", "translatedTitle": "Get ready for Algebra 1"},
        {"slug": "get-ready-for-geometry", "translatedTitle": "Get ready for Geometry"},
        {"slug": "get-ready-for-algebra-ii", "translatedTitle": "Get ready for Algebra 2"},
        {"slug": "get-ready-for-precalculus", "translatedTitle": "Get ready for Precalculus"},
    ]},

which would need to be added manually somewhere in the curation.py for en, en/us-cc, and possibly en/in-in.

This was reported on the forums, see https://community.learningequality.org/t/update-khan-academy-math-content/1634/2

General procedure

1. Watch the logs for WARNING (in case certain slugs are removed)
2. Periodically audit the curation.py and compare with website {lang}.khanacademy.org and output of /graphql.py --lang {lang} to see if new things added
3. Periodically do "deep audit" ./katrees.py --print --printmaxlevel=3 --lang {lang} to see the tree returned from the API and see if there are new slugs that should be added somewhere in curation.py or skipped by adding to SLUG_BLACKLIST (in case of unsupportd types, empty folders, or other parts of the KA that we don't want to import).