Bugfix/wsl error

[Ttayu]

An error occurred when running PasteImg on WSL.
Also, is_clipboard_img was returning True when there is no images in the Clipboard.

=Get-Clipboard : The term '=Get-Clipboard' is not recognized as the name of a cmdlet, function, script file, or operable program.
Check the spelling of the name, or if a path was included, verify that the path is correct and try again.
At line:1 char:1
+ =Get-Clipboard -Format Image
+ ~~~~~~~~~~~~~~
    + CategoryInfo          : ObjectNotFound: (=Get-Clipboard:String) [], CommandNotFoundException
    + FullyQualifiedErrorId : CommandNotFound

Version

• neovim: v0.9.0-dev
• powershell: 5.1.19041.1682
• WSL2: Ubuntu 22.04.1 LTS