Add Telegram Commenting Systems and fix Russian translation (#817)

### Prerequisites

Put an `x` into the box(es) that apply:

- [X] This pull request fixes a bug.
- [X] This pull request adds a feature.
- [ ] This pull request introduces breaking change.

### Description

With the Comments.App tool, site owners can add a comment widget to
their site. With it, Telegram users can leave comments, attach images to
them, give likes and dislikes, and reply to other commenters.

### Issues Resolved

The ending of one of the words did not fit the context.

### Checklist

Put an `x` into the box(es) that apply:

#### General

- [X] Describe what changes are being made
- [X] Explain why and how the changes were necessary and implemented
respectively
- [ ] Reference issue with `#<ISSUE_NO>` if applicable

#### Resources

- [ ] If you have changed any SCSS code, run `make release` to
regenerate all CSS files

#### Contributors

- [X] Add yourself to `CONTRIBUTORS.md` if you aren't on it already