Misleading install instructions in Screenshots doc

At the top of the [Screenshots](https://docs.fastlane.tools/getting-started/ios/screenshots/) page, there's a summary of install instructions that say:

```
2) Install fastlane

# Using RubyGems
sudo gem install fastlane -NV

# Alternatively using Homebrew
brew install fastlane
```

Below it, there's a [Read More](https://docs.fastlane.tools/getting-started/ios/screenshots/) link that contains the actual instructions that recommend NOT doing exactly what the instructions in the Screenshots page say.

I think that step 2 of the instructions should just point to the "Read More" link, not lead you to install fastlane using your system ruby version.