Rename users documentation to user
All other instances are singular except this one. This unifies the sphinx instance name to singular.
Related to #3650 (closed)
Test Plan
make -C user clean html is fine
Migrated from D6467 (view on Phabricator)
All other instances are singular except this one. This unifies the sphinx instance name to singular.
Related to #3650 (closed)
make -C user clean html is fine
Migrated from D6467 (view on Phabricator)