[docs][guides] new page on top errors with troubleshooting advice

[marcysutton]

Summary

To support people of all skill levels building Gatsby sites, we want to add a Reference Guide with the top errors and how to fix them. This would live in the Debugging Gatsby section, and could have a title of "Common Errors and Troubleshooting" or something to that effect.

Some potential subtopics to include:

• Node/Sharp issues
• data sourcing errors
• GraphQL errors
• errors from common plugins

Structure

A reference guide explains a Gatsby concept or technique without the step-by-step context provided by a tutorial or recipe. Refer to the contributing docs for a reference guide template and the Gatsby Style Guide for writing conventions.

Audience

Beginner to novice developers with a limited understanding of Gatsby or GraphQL should be able to follow along with this guide to debug and try to lead them to a solution. As we say in the Style Guide, avoid jargon and assumed knowledge of terminology or extremely technical conventions.

Motivation

To help people building Gatsby sites solve their issues, so they can move onto something else! Easier debugging means happier development usually.

Approach

Due to how big this issue is we're going to note various stages of work that we expect to complete.
[ ] - Error messages and debugging
[ ] - Behavior errors (e.g. it works on develop and not built)
[ ] - Interactive page that allows for feedback of top bugs, a component to upvote and help us surface that most common errors and issues

[gillkyle]

Discussing this errors on the team led to some additional ideas and notes for this:

• including the full strings of errors (sort of like a GitHub issue might) will be helpful for search and SEO
• when is a gatsby clean necessary to clean out the internal cache?
• the @gatsbyjs/core might have some better insight into what issues show up most frequently and aren't just things that have already been patched

[gillkyle]

We added this guide in #19966, I'll close now, though the ideas in original post could add some more cool functionality!