Improve command resolution in !help

[RamblingCookieMonster]

Noticed that some Get-CommandHelp calls were returning more data than expected (i.e. Manual field for commands with similar names shows doesn't show expected content with -Examples, -Detailed, or -Full).

Description

• Look in FullCommandName, Aliases, Comman independently, vs. -or comparisons, which may return more than one result and change behavior
• Use pluginmanager.commands.ModuleCommand to fully qualify get-help call - this ensures the specific fully qualified command name is queried for help

Related Issue

#67 ish

Motivation and Context

I keep getting output for multiple commands when using -Detailed, -Full, and -Examples, for certain commands

How Has This Been Tested?

Manually tested against a variety of commands that previously generated multiple items in the Manual field, now see expected content

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[devblackops]

Good catch @RamblingCookieMonster. Thanks!