Improves documentation about new typescript version requirement

[mradcliffe]

As a current extension user :wave:, when the extension updates and breaks compatibility with older versions of TypeScript, I should be able to clearly see the new requirement after the extension automatically updates. I am less likely to look in Configuration because I have already configured the extension.

It took much issue searching trying to figure out how to debug why tslint no longer was working (reading through #54, #72, #61). I did look at the extension page, but I did not seem to notice the new requirement. Eventually I was able to enable verbose logging, see that typescript-tslint-plugin had a cryptic (now clear) version requirement for TypeScript, and realize that I can no longer use the extension for all my projects. Finally, I did find the "TS 3.2+" mentioned in the Configuration section.

I took a stab at improving the documentation.

I wasn't sure whether to combine the current "important" notice or not, but I ended up doing so trying to write concisely that a user can both use this extension on newer projects and explicitly disable it and enable the deprecated extension on older projects. I couldn't find the best documentation page to link to to explain the "Enable/Disable (Workspace)" option.

Hopefully it makes it clearer, sooner, when looking at the extension page. :-)

As a follow-up, there might be a way to look for the version requirement in typescript-tslint-plugin and then report that directly to the user without logging it to a file.

[mjbvz]

I don't think this is correct. The tslint-plugin that provides intellisense does only require TS 3.0. Here it is working with TS 3.0.3:

Configuration syncing between vscode and the plugin requires TS 3.2+. I'd say this should be documented in the setting descriptions themselves instead of in the README. These are in the package.json. @mradcliffe Do you want to look into adding that?

[mjbvz]

Closing this as changes are needed