Minor doc fixes

This PR should be considered after !10 (merged) is merged as its based on it.

This PR contains multiple small fixes:

• documentation for path command
• wording
• missed dots
• multiline code examples made to fit on the screen where seemed possible
• triple code fences for inline commands swapped to single ones

The live preview is available here https://rdodin.gitlab.io/gnmiclient-docs/