text: Title: Fix broken links in doc
  Body: The doc/ directory contains our documentation. Some files there link to our [projects](https://github.com/ploomber/projects) repo, however, we're rolling out a folder layout change soon, which you can see by going to the [layout branch](https://github.com/ploomber/projects/tree/layout)
  
  To avoid confusion: this issue is about fixing links on this repo that point to https://github.com/ploomber/projects
  
  Example:
  
  `spec-api-python` in the master branch, becomes `guides/spec-api-python` in the layout branch.
  
  
  We need help updating those links, essentially we need to look for links containing `https://github.com/ploomber/projects/tree/master` then update the last part to match the new layout.
  
  e.g.
  
  `https://github.com/ploomber/projects/tree/master/spec-api-python`
  
  becomes
  
  `https://github.com/ploomber/projects/tree/master/guides/spec-api-python`
  
  
  Here's an example of a file that needs an update: https://github.com/ploomber/ploomber/blob/master/doc/cookbook/grid.rst
  
  note that the last link is: https://github.com/ploomber/projects/blob/master/mlflow/README.ipynb
  
  However `mlflow` ([master branch)](https://github.com/ploomber/projects/tree/master/mlflow) moved to `templates/mlflow` ([layout branch)](https://github.com/ploomber/projects/tree/layout/templates/mlflow)
  
  