Hide the numbering in the md book output

[chancancode]

See https://emberjs.github.io/rfcs/

We want to change this:

1. 0001-transform-attribute-meta-parameter
2. 0003-block-params
3. 0003-cli-ember-doctor
4. 0010-engines
5. 0011-improved-cp-syntax
6. 0012-help-json-output
7. 0015-the-road-to-ember-2-0
8. 0020-sri-default
9. ...

...into this...

0001-transform-attribute-meta-parameter
0003-block-params
0003-cli-ember-doctor
0010-engines
0011-improved-cp-syntax
0012-help-json-output
0015-the-road-to-ember-2-0
0020-sri-default
...

...or ideally, even this...

#1. Pass through attribute meta data to related Transform
#3 Block Params
#3 ember doctor
#10 Engines
...

We should be able to do the middle thing quickly with CSS, but maybe this is something we should PR to upstream (mdbook).

[makepanic]

the second option already works when configuring mdbook with:

[output.html]
no-section-label = true

see https://rust-lang-nursery.github.io/mdBook/format/config.html#html-renderer-options

It seems like that option isn't supported in 0.0.26. I've installed the latest one and the output is as expected:

I can open a PR which adds the config and bumps mdbook if you want

It seems like that option was supported for a very long time. Let me recheck if it works on .26 it was added in 0.1.0 but this repo still uses 0.0.26

[chancancode]

@makepanic yes please 🙏

[makepanic]

created #526 to fix this issue