Add Subito custom reporter

Source/SwiftLintCore/Models/ReportersList.swift

@@ -16,6 +16,7 @@ public let reportersList: [any Reporter.Type] = [
     RelativePathReporter.self,
     SARIFReporter.self,
     SonarQubeReporter.self,
+    SubitoReporter.self,
     SummaryReporter.self,
     XcodeReporter.self,
 ]

Source/SwiftLintCore/Reporters/SubitoReporter.swift

@@ -0,0 +1,46 @@
+/// Reports violations in the custom Subito format.
+struct SubitoReporter: Reporter {
+    // MARK: - Reporter Conformance
+
+    static let identifier = "subito"
+    static let isRealtime = false
+    static let description = "Reports violations in the custom Subito format."
+
+    static func generateReport(_ violations: [StyleViolation]) -> String {
+        violations
+            .group { $0.location.file ?? "Other" }
+            .sorted { $0.key < $1.key }
+            .map(report)
+            .joined(separator: "\n\n")
+    }
+
+    /// Generates a report for a single violation.
+    ///
+    /// - parameter violation: The violation to report.
+    ///
+    /// - returns: The report for a single violation.
+    private static func report(for file: String, with violations: [StyleViolation]) -> String {
+        // {emoji} {error,warning}
+        //   {full_path_to_file}{:line}{:character}
+        //   {content} - {content}
+        violations
+            .sorted { $0.severity == $1.severity ? $0.location > $1.location : $0.severity > $1.severity }
+            .map { violation in
+                let emoji, severityColor: String, locationColor = "\u{001B}[0;36m", resetColor = "\u{001B}[0;0m"
+                switch violation.severity {
+                case .error:
+                    emoji = "⛔️"
+                    severityColor = "\u{001B}[0;31m"
+                case .warning:
+                    emoji = "⚠️"
+                    severityColor = "\u{001B}[0;33m"
+                }
+                return """
+                \(emoji) \(severityColor)\(violation.severity.rawValue)\(resetColor)
+                  \(locationColor)\(violation.location)\(resetColor)
+                  \(violation.ruleName) Violation - \(violation.reason) \(violation.ruleIdentifier)
+                """
+            }
+            .joined(separator: "\n\n")
+    }
+}