Error in Operator implementation guide

[apeforest]

Description

Error in the operator implementation guide:
https://mxnet.incubator.apache.org/faq/add_op_in_backend.html

It's correct in the markdown file: https://github.com/apache/incubator-mxnet/blob/master/docs/faq/add_op_in_backend.md

Error Message:

"Note that forward and backward functions are registered with attribute key FCompute, rather than FCompute."

[apeforest]

@mxnet-label-bot could you please add [Doc] here?

[apeforest]

@nswamy Please label [Doc] for this issue. Thanks

[anirudhacharya]

@apeforest there is an ongoing PR to update the operator implementation guide - #12230 If you could comment there about what issue you found in the tutorial, it can be fixed in that PR itself.

[apeforest]

@anirudhacharya The markdown file in the github is correct. The problem happens in the html generation.

[apeforest]

@nswamy This error is not related to Operator. It is purely a html error. Please remove the [Operator] label and changed it to [Doc]. Thanks!

[aaronmarkham]

I think I found the culprit.
The md-->html build when you do make html or make docs gives you things like <gpu> which renders fine in the browser.

There's a post-process step for building the versioned website that uses beautiful soup to inject the modified nav bar. It also has a step that swaps out the html tags for < and > with actual < and >.
https://github.com/apache/incubator-mxnet/blame/master/docs/build_version_doc/AddVersion.py#L77

So, introduce this AddVersion.py script and it swaps it back to <gpu>. You can see this in the website static files that have gone through this process:
https://github.com/apache/incubator-mxnet-site/blob/asf-site/faq/add_op_in_backend.html#L751
This does not render properly. This is the same thing happening with the scala tutorial: #11438

I can remove that line, but I don't know why it's there in the first place. @piiswrong - you authored it... do you remember what it is for? Can we safely remove it, or provide a more focused implementation so it doesn't break the tags we're trying to put in there?

EDIT: I commented that line out and reran the process on master, and the output is fixed. Not sure if something somewhere is broken though...
http://34.201.8.176/versions/tag_render/faq/add_op_in_backend.html

It also fixes the tags in scala tutorial: