Make documentation guidelines easier to discover (#600)

* Make documentation guidelines easier to discover

* Move documentation page under engineering, renaming it to `product_documentation.md` and add a link to editing the handbook on the homepage

* Clarify that the documentation guidelines are for Sourcegraph the product, not the handbook

Co-authored-by: Nick Snyder <nickdsnyder@gmail.com>

handbook/engineering/index.md

@@ -7,6 +7,7 @@
 - [Code reviews](code_reviews.md)
 - [Go style guide](go_style_guide.md)
 - [Testing](testing.md)
+- [Product documentation](product_documentation.md)
 - [Continuous releasability](continuous_releasability.md)
 - [Commit message guidelines](commit_messages.md)
 - [Incidents](incidents.md)

handbook/documentation/index.md → handbook/engineering/product_documentation.md

@@ -1,6 +1,8 @@
-# Sourcegraph documentation guidelines
+# Product documentation
 
-## Contributing to documentation
+These guidelines are for contributing documentation to the [sourcegraph repository](https://github.com/sourcegraph/sourcegraph/tree/master/doc). See [editing the handbook](../editing.md) for how to contribute handbook content.
+
+## Contributing
 
 Whenever a feature is changed, updated, introduced, or deprecated, the pull request introducing these changes must be accompanied by the documentation (either updating existing ones or creating new ones).
 

handbook/index.md

@@ -6,6 +6,7 @@ The Sourcegraph handbook describes how we (Sourcegraph teammates) work. It's pub
 
 - [Strategy](../company/strategy.md)
 - [Handbook usage](usage.md)
+- [Editing the handbook](editing.md)
 - [Communication](communication/index.md)
   - [Style guide](communication/style_guide.md)
 - [Team](../company/team/index.md)

handbook/usage.md

@@ -29,7 +29,9 @@ Join the `#handbook` Slack channel to see proposed changes.
    - In your message announcing the change, just include `[Handbook/process] change:`, the commit message subject, and the link. Don't write a separate summary of the change (if you feel the need to do so, you should have used a better commit message).
    - Ensure everyone who needs to be aware of the change is made aware. If you see people do things that indicate they aren't aware, gently remind them of the change. If you don't nudge them, other people will see them doing things the wrong/old way and start to doubt the handbook's accuracy or currency.
 1. Strongly prefer creating a pull request over filing an issue on the handbook or mentioning it on Slack, even if you aren't able to propose the full edits you'd like to make.
-1. Follow the [style guide](communication/style_guide.md) and [documentation guidelines](documentation/index.md) when making changes to the handbook.
+1. Follow the [style guide](communication/style_guide.md).
+
+> NOTE: If your contribution is about using or configuring Sourcegraph (the product), it most likely belongs in the [product documentation](engineering/product_documentation.md).
 
 ## Why handbook-first?