Fix typo documentation & update RU translations

[ghost]

My PR is a:

• 💥 Breaking change
• 🐛 Bug fix #issueNumber
• 💅 Enhancement
• 🚀 New feature

Main update on the:

• Admin
• Documentation
• Framework
• Plugin

[derrickmehaffy]

Good catch, if you don't mind can I have you throw another typo in this PR?

Can you stick this bit:

#### Relations
 You can also use filters into a relation attribute which will be applied to the first level of the request.
 Find users having written a post named `Title`.
 
 `GET /users?posts.name=Title`
 
 Find posts written by a user having more than 12 years old.
 
 `GET /posts?author.age_gt=12`
 
 > Note: You can't use filter to have specific results inside relation, like "Find users and only their posts older than yesterday" as example. If you need it, you can modify or create your own service or use [GraphQL](./graphql.md#query-api).

 > Warning: this filter isn't available for `upload` plugin

In: https://github.com/strapi/strapi/edit/master/docs/3.x.x/guides/filters.md

I made a few fixes there, and easier than creating another PR 😛

[lauriejim]

LGTM thank you for this update!