Update oh-my-posh.ts to fix an error in the "config export" command description

[RomainFon]

Fixed an error in the description of the "oh-my-posh config export" command.

[withfig-bot]

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[withfig-bot]

Overview

src/oh-my-posh.ts:

Info:

[withfig-bot]

Hello @RomainFon,
thank you very much for creating a Pull Request!
Here is a small checklist to get this PR merged as quickly as possible:

• Do all subcommands / options which take arguments include the args property (args: {})?
• Are all options modular? E.g. -a -u -x instead of -aux
• Have all other checks passed?

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[RomainFon]

I have read the CLA Document and I hereby sign the CLA