Clarify "job etag mismatch" situation

When a submitted job is refused because of a mismatched etag, there is
now a more explanatory error logged on the Manager. The website also has
an entry in the FAQ for this, as I expect more people to run into this
issue when they upgrade Flamenco.

.gitignore

@@ -33,6 +33,7 @@ __pycache__
 web/manager-api/dist/
 web/static/
 web/project-website/public/
+web/project-website/resources/_gen/
 /dist/
 /tools/
 

internal/manager/api_impl/jobs.go

@@ -94,8 +94,8 @@ func (f *Flamenco) SubmitJob(e echo.Context) error {
 	authoredJob, err := f.jobCompiler.Compile(ctx, submittedJob)
 	switch {
 	case errors.Is(err, job_compilers.ErrJobTypeBadEtag):
-		logger.Warn().Err(err).Msg("rejecting submitted job, job type etag does not match")
+		logger.Warn().Err(err).Msg("rejecting submitted job because its settings are outdated, refresh the job type")
-		return sendAPIError(e, http.StatusPreconditionFailed, "rejecting job, job type etag does not match")
+		return sendAPIError(e, http.StatusPreconditionFailed, "rejecting job because its settings are outdated, refresh the job type")
 	case err != nil:
 		logger.Warn().Err(err).Msg("error compiling job")
 		// TODO: make this a more specific error object for this API call.

web/project-website/content/faq/_index.md

@@ -6,6 +6,13 @@ weight: 30
 This is a list of frequently asked questions, with their answers. It's by no
 means an exhaustive list.
 
+## What do "Error: Cached job type is old" or "job type etag does not match" mean?
+
+This means that you have to click on the little "Refresh" icon next to the job type:
+
+<img src="job-types-refresh.webp" width="396" height="41">
+
+
 ## ​What's the difference with OpenCue?
 
 OpenCue is aimed at a different audience than Flamenco. OpenCue is a large and