docs(*): update deprecated comments, contributing guide; fix tags

[damyanpetev]

We've been doing the @deprecated JSDoc tags wrong, since almost all tags are block so placing them on the top of the comment description consumes it as well as part of the tag:

So I've updated all the comments and adjusted the Contributing Guidelines accordingly.

Also found a widespread use of @Input in the comments as a tag (without backticks) which breaks the comments further:

and removed all of those uses. If we still want to additional meta for that property in the API Docs, that can be either automated or the new signal inputs will likely force it anyway from the different return type if/when we start using them.

Bonus: Mainly due to some spelling errors, adding the following as VS Code recommendations for extensions in the project:

• editorconfig.editorconfig EditorConfig for the .editorconfig file support (already present in the repo)
• dbaeumer.vscode-eslint ESLint integration
• angular.ng-template Angular Language Service
• streetsidesoftware.code-spell-checker Code Spell Checker for those pesky typos
  Let me know if more should be added to the list. Also considering a section in the guidelines somewhere

Additional information (check all that apply):

• Bug fix
• New functionality
• Documentation
• Demos
• CI/CD

Checklist:

• All relevant tags have been applied to this PR
• This PR includes unit tests covering all the new code (test guidelines)
• This PR includes API docs for newly added methods/properties (api docs guidelines)
• This PR includes feature/README.MD updates for the feature docs
• This PR includes general feature table updates in the root README.MD
• This PR includes CHANGELOG.MD updates for newly added functionality
• This PR contains breaking changes
• This PR includes ng update migrations for the breaking changes (migrations guidelines)
• This PR includes behavioral changes and the feature specification has been updated with them