style: add media-query to resize font-size on high dpi screens

[idleberg]

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Identify the Bug

https://github.com/atom-community/tool-bar/issues/353

Description of the Change

This PR adds a media-query addressing high DPI screens:

• min-device-pixel-ratio: 2: This condition checks if the device's pixel ratio is at least 2. This is typically used for high-resolution displays like Retina screens.

• min-resolution: 192dpi: This condition checks if the device's resolution is at least 192 dots per inch (dpi).

• min-resolution: 2dppx: This condition checks if the device's resolution is at least 2 dots per pixel (dppx). This is another way to specify high-resolution displays.

Alternate Designs

Possible Drawbacks

Verification Process

Release Notes

Adds media-query for high DPI screen that enlarges all icons by 200%

[idleberg]

I tested it on a Dell XPS with HiDPI and an Apple Studio Display, but somebody else should probably verify this. Also, make sure that the icons look fine on "normal" displays.