Add example on docs and /examples folder

[Slushee-a]

Why

As mentioned in #65, two improvements that could be made were adding another example project and expanding documentation on set_pixels()

Changes included

• Adds another example to the /examples folder.

  • Made for the esp32-c3
  • Using the ili9486 display with SPI
  • Shows a basic example of howset_pixels() can be used

• Adds an example to the set_pixels() on the docs

[Slushee-a]

Changes included on the latest commit:

• Removed map example from set_pixels, swapped directly with an Rgb666 array instead
• Removed map + set_pixels segment from spi-ili9486-esp32-c3 example in favor of fill_contiguous with an Rgb565 array
• Added an example drawing of a basic smiley face on the spi-ili9486-esp32-c3 example
• Fix typo
• Fix dependency usage

[Slushee-a]

Changes included on the latest commit:

• Switched away from Rectangle::with_corners in favor of Rectangle::new
• Move smiley face drawing from main to a separate function
• Remove outdated comment (Sorry!)
• Explain set_pixels() behavior instead of warning

[Slushee-a]

I do agree with the fact that the fill_contiguous part of the example should be removed, since drawing basic shapes is already enough for the example.

Adding a link to the embedded-graphics examples is a great idea. Should it be added to the docs homepage or to the README?

[rfuest]

Adding a link to the embedded-graphics examples is a great idea. Should it be added to the docs homepage or to the README?

Both locations would make sense, some users might learn about the crate via the README while others read the docs first. The README already contains a reference to e-g with this sentence: "embedded-graphics-core is used to provide the drawing API.", but that isn't very useful for users of the crate IMO. The distinction between embedded-graphics-core and embedded-graphics should be considered an implementation detail and not something that is important for users. A short description what e-g is and links to the relevant docs would be more useful than a link to e-g-core.