Add newline after declarations

Author: kimdv

Sources/SwiftParserDiagnostics/ParseDiagnosticsGenerator.swift

@@ -1046,8 +1046,16 @@ public class ParseDiagnosticsGenerator: SyntaxAnyVisitor {
           position: position,
           .consecutiveDeclarationsOnSameLine,
           fixIts: [
-            FixIt(message: .insertSemicolon, changes: .makePresent(semicolon))
-          ],
+            node.lastToken(viewMode: .sourceAccurate).map {
+              FixIt(
+                message: .insertNewline,
+                changes: [
+                  .replaceTrailingTrivia(token: $0, newTrivia: .newlines(1))
+                ]
+              )
+            },
+            FixIt(message: .insertSemicolon, changes: .makePresent(semicolon)),
+          ].compactMap { $0 },
           handledNodes: [semicolon.id]
         )
       } else {

Tests/SwiftParserTest/translated/ConsecutiveStatementsTests.swift

@@ -102,8 +102,8 @@ final class ConsecutiveStatementsTests: XCTestCase {
       }
       """,
       diagnostics: [
-        DiagnosticSpec(locationMarker: "1️⃣", message: "consecutive declarations on a line must be separated by ';'", fixIts: ["insert ';'"]),
-        DiagnosticSpec(locationMarker: "2️⃣", message: "consecutive declarations on a line must be separated by ';'", fixIts: ["insert ';'"]),
+        DiagnosticSpec(locationMarker: "1️⃣", message: "consecutive declarations on a line must be separated by ';'", fixIts: ["insert newline", "insert ';'"]),
+        DiagnosticSpec(locationMarker: "2️⃣", message: "consecutive declarations on a line must be separated by ';'", fixIts: ["insert newline", "insert ';'"]),
         DiagnosticSpec(locationMarker: "3️⃣", message: "consecutive statements on a line must be separated by ';'", fixIts: ["insert ';'"]),
         DiagnosticSpec(locationMarker: "4️⃣", message: "consecutive statements on a line must be separated by ';'", fixIts: ["insert ';'"]),
         DiagnosticSpec(locationMarker: "5️⃣", message: "consecutive statements on a line must be separated by ';'", fixIts: ["insert ';'"]),