DOC Update react injector docs to work

[GuySartorelli]

Reapplies the changes to graphql injector docs that were (meant to be) reverted (along with any new changes I found that were required)

NOTE

The revert commit was not completed correctly. It was meant to revert the entirety of #187 and #197, but failed to do so!
That's okay because this commit would have partially reinstated those PRs anyway.

Make sure you test and review the entirety of the graphql/javascript code from ## Using Injector to customise GraphQL queries to the end of the file. That includes both the graphql 3 and graphql 4 sections! ALL of that is in scope for this PR.

Requires extra admin PR also

• FIX Make graphql mutation template abstractions work silverstripe-admin#1498

Issue

• Update docs from graphql 3 to graphql 4 compatability #62

[sabina-talipova]

Could we also fix this small spelling issue cient to client.

developer-docs/en/02_Developer_Guides/15_Customising_the_Admin_Interface/07_ReactJS_Redux_and_GraphQL.md

Line 1412 in 1a9525d

**my-module/cient/src/state/createNote.js**

And small question: why we use somewhere app/client and in another places my-module/client?

[GuySartorelli]

why we use somewhere app/client and in another places my-module/client?

It's to distinguish between the two contexts this documentation is bouncing between - there's a module which provides the notes components and the actual DataObject implementation, and then there's some app project which is customising that component by adding the priority field.

Really this whole section of docs needs to be reconsidered, probably being split into a more traditional "here is the API and how it works" and then these examples should be moved into a "how to" section and fleshed out a bit more. But that's not in scope for this PR where I'm just trying to make sure the examples work at all.

[sabina-talipova]

Really this whole section of docs needs to be reconsidered, probably being split into a more traditional "here is the API and how it works" and then these examples should be moved into a "how to" section and fleshed out a bit more. But that's not in scope for this PR where I'm just trying to make sure the examples work at all.

We should, probably, update this section. Since information presented in ## Using Injector to customise GraphQL queries section is not enough to use it as an example for testing.

[sabina-talipova]

Could you fix spelling mistake cient to client

developer-docs/en/02_Developer_Guides/15_Customising_the_Admin_Interface/07_ReactJS_Redux_and_GraphQL.md

Line 1412 in 1a9525d

**my-module/cient/src/state/createNote.js**

[GuySartorelli]

We should, probably, update this section. Since information presented in ## Using Injector to customise GraphQL queries section is not enough to use it as an example for testing.

I've made a note about this in #129, which is about reviewing the structure and general content of front-end related documentation. It falls outside the scope of this PR, which is really just about making the graphql code examples work - not necessarily about making them clear and easy to understand.

In other words, we'll do this in stages:

• Stage one is getting the code example to work at all. That's this PR
• Stage two is restructuring the doc so that the code example and API documentation are separate, and independently easy to follow. That's Review all front-end-related documentation #129

For the purposes of testing this PR, I'll send you the project I used to do so with information about how to use it for testing this PR.

[GuySartorelli]

I've fixed the typo.

[sabina-talipova]

LGFM