Docs: explain in CONTRIBUTING.md how to run a Jest build from another… (#2858)
Docs: explain in CONTRIBUTING.md how to run a Jest build from another… (#2858)

* Docs: explain in CONTRIBUTING.md how to run a Jest build from another project

* move new section, delete point, fix 2 headings

facebook/jest,bookman25/jest,cpojer/jest,ide/jest,skovhus/jest,cpojer/jest,cpojer/jest,facebook/jest,mpontus/jest,skovhus/jest,mpontus/jest,ide/jest,bookman25/jest,bookman25/jest,facebook/jest,ide/jest,skovhus/jest,mpontus/jest