pricop

Results 3 issues of pricop

When converting an `rgba` or `hlsa` color with alpha opacity value to `hexa`, the result is not as expected (see attachment). ![image](https://user-images.githubusercontent.com/920945/175218106-31ec5c88-d3e9-4b20-85e0-6e3339be8f53.png)

hacktoberfest

### Prerequisites - [X] I have [searched](https://github.com/twbs/bootstrap/issues?utf8=%E2%9C%93&q=is%3Aissue) for duplicate or closed issues - [X] I have [validated](https://html5.validator.nu/) any HTML to avoid common problems - [X] I have read the [contributing...

css

Rather than returning a string (which can differ, based on the selected language), let's return a boolean instead. We can then do the validation in the Controller based on the...