There was some confusion over whether `code` or `content` is the right
parameter for snippets. Internally, the database stores
`content`. However:

1. Project snippets use `code`. `code` gets remapped in `content` in
`lib/api/project_snippets.rb`.

2. Personal snippets use `content`.

In GitLab 12.3,
https://gitlab.com/gitlab-org/gitlab-foss/merge_requests/32296
standardized the APIs to use `content` while allowing the deprecated
`code` field to be used for project snippets.