Rule Request: [GuardIfSwitchReturnOnSameLine]

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• [*] Updated SwiftLint to the latest version
• [*] I searched for existing GitHub issues

New rule request

Please describe the rule idea, format
this issue's title as Rule Request: [Rule Name] and describe:

1. Why should this rule be added? Share links to existing discussion about what
   the community thinks about this.

Conditionals and switch returning in same line, when the line is short enough, are more readable. This is a rule implementing the opposite as SwitchCaseOnNewlineRule and ConditionalsReturnOnNewLine.

2. Provide several examples of what would and wouldn't trigger violations.

wouldn't:

        guard parameter1.isEmpty else { return }
        
        switch parameter1 {
        case "option1": return
        default: break
        }

would:

        guard parameter1.isEmpty else {
            return
        }
        
        switch parameter1 {
        case "option1":
            return
        default:
            break
        }

3. Should the rule be configurable, if so what parameters should be configurable?

Yes. The length of the line, to distinguish when it should be on the same line as de conditional.
Also, is should provide an option to select when the rule applies: if, guard or switch. Something like:

guard_if_switch_return_on_same_line:
  lineLengthThreshold: 40
  error: 
    - if
    - guard
    - switch

4. Should the rule be opt-in or enabled by default? Why?
   See README.md for guidelines on when to mark a rule as opt-in.

Opt-in, as ConditionalsReturnOnNewLine.

Start with README.md's opt-in rules guidance and inspect the existing ConditionalsReturnOnNewLine and SwitchCaseOnNewlineRule implementations. Define the requested line-length threshold and if/guard/switch selection from the examples, then verify that short single-line forms pass and expanded forms are reported according to the configuration.