Improve grammar for single periodic second/minute/hour

[Bwooce]

Trigger every 1 hours -> Trigger every hour
Trigger every 1 minutes -> Trigger every minute
Trigger every 1 seconds -> Trigger every second

(and combinations thereof)

Proposed change

Grammar annoyed me for single periodic triggers, so here's a small fix

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New feature (thank you!)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Example configuration

Automation like so, redundant intervals just to demo in one go (/1 second would be enough...):

alias: Trigger every second of every minute of every hour 
description: ""
trigger:
  - minutes: /1
    platform: time_pattern
    hours: /1
    seconds: /1
condition:
action:
mode: single

Additional information

• This PR is related to issue or discussion: Add a description for time pattern trigger home-assistant/frontend#16520 (augments slightly)
• Link to documentation pull request:

Checklist

• The code change is tested and works locally.
• There is no commented out code in this PR.
• Tests have been added to verify that the new code works.

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated for www.home-assistant.io