Token filters - edge_ngram [DOC]

[AntonEliatra]

What do you want to do?

• Request a change to existing documentation
• Add new documentation
• Report a technical problem with the documentation
• Other

Create a separate page for Token filter: edge_ngram

Part of META issue: #1483

*Version: all

[AntonEliatra]

@Naarcha-AWS I can take this one