[docs] address missing topics in docs

[flynnduism]

Reviewing analytics from the search feature, about 7% of all searches queries have no match to the docs content. This data is based off the latest Helm 2 docs.

Filing this issue as a reference - as we work on documentation tidy-ups it would be great to include info on any of these topics to guide users who have these kinds of queries.

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Data of top 10 'no result' queries:

1. volume               82 searches
2. b4enc                40 
3. atomic               27
4. imagePullSecrets     24
5. toJson               23
6. cronJob              22
7. concat               21
8. nameOverride         21
9. volumeMounts         19
10. tojson              16

A full .csv of the top 'no result' results can be seen here. It is based off search queries over the last 90 days.

[bridgetkromhout]

@flynnduism it would be really interesting to see an update of this data, if you can provide it. Thanks!

[flynnduism]

Here's a CSV of search data from the last 90 days.

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Top 25 searches at a glance:

[flynnduism]

Adding to this, here is recent (3 month) user search data which returned no results on the site. (full CSV).

I'm tagging this as a good first issue, it would be great if any contributors could add context around these subjects. Adding notes, redirects or background for things that don't exist would help bring clarity. See #726 for an example of this.

[bacongobbler]

Thanks for the reporting here, @flynnduism.

I checked a few of the search topics in here. A couple of these search topics all relate to function calls available in Helm's template calls. tojson, b64enc, concat, haskey, trimsuffix and randalphanum all resolve to their function definitions, so that knocks a few off the list.

if you search for "image pull secrets" instead of "imagepullsecrets", https://helm.sh/docs/howto/charts_tips_and_tricks/#creating-image-pull-secrets comes up. Is there a way to create aliases for search terms with algolia?

For "atomic", they're probably looking for documentation on the --atomic flag. A code search query on github only shows this as documentation for helm help. This looks like a good area to document: https://github.com/helm/helm-www/search?q=--atomic&unscoped_q=--atomic

For "proxy", I'm assuming they're referring to HTTP_PROXY or other related proxy setup environment variables, which may also be useful to document.

Not sure what we can do about "nameoverride".

As for the other search terms, it looks like users are trying to look for information on specific charts. They should probably be using CNCF Artifact Hub instead.