chore(shorebird_cli): prettify doctor output formatting (#2167)

packages/shorebird_cli/lib/src/doctor.dart

@@ -1,3 +1,5 @@
+import 'dart:convert';
+
 import 'package:mason_logger/mason_logger.dart';
 import 'package:scoped_deps/scoped_deps.dart';
 import 'package:shorebird_cli/src/logger.dart';
@@ -100,7 +102,20 @@ class Doctor {
       }
 
       for (final issue in unresolvedIssues) {
-        logger.info('  ${issue.displayMessage}');
+        if (issue.displayMessage == null) {
+          continue;
+        }
+
+        final lines = const LineSplitter().convert(issue.displayMessage!);
+        for (final (i, line) in lines.indexed) {
+          var leadingPaddingSpaceCount = 2;
+          if (i > 0) {
+            // Indent subsequent lines to align with the first line after the
+            // leading string and the space following it.
+            leadingPaddingSpaceCount += issue.severity.rawLeading.length + 1;
+          }
+          logger.info('${' ' * leadingPaddingSpaceCount}$line');
+        }
       }
 
       allIssues.addAll(unresolvedIssues);

packages/shorebird_cli/lib/src/validators/validators.dart

@@ -22,12 +22,21 @@ enum ValidationIssueSeverity {
 
 /// Display helpers for printing [ValidationIssue]s.
 extension Display on ValidationIssueSeverity {
-  String get leading {
+  String get rawLeading {
     switch (this) {
       case ValidationIssueSeverity.error:
-        return red.wrap('[✗]')!;
+        return '[✗]';
       case ValidationIssueSeverity.warning:
-        return yellow.wrap('[!]')!;
+        return '[!]';
+    }
+  }
+
+  String get displayLeading {
+    switch (this) {
+      case ValidationIssueSeverity.error:
+        return red.wrap(rawLeading)!;
+      case ValidationIssueSeverity.warning:
+        return yellow.wrap(rawLeading)!;
     }
   }
 }
@@ -52,7 +61,7 @@ class ValidationIssue {
 
   /// A console-friendly description of this issue.
   String? get displayMessage {
-    return '${severity.leading} $message';
+    return '${severity.displayLeading} $message';
   }
 
   // coverage:ignore-start

packages/shorebird_cli/test/src/doctor_test.dart

@@ -12,7 +12,9 @@ void main() {
   group(Doctor, () {
     const validationWarning = ValidationIssue(
       severity: ValidationIssueSeverity.warning,
-      message: 'warning',
+      message: '''
+warning
+with multiple lines''',
     );
     const validationError = ValidationIssue(
       severity: ValidationIssueSeverity.error,
@@ -75,18 +77,10 @@ void main() {
           verify(validator.validate).called(1);
         }
 
-        verify(
-          () =>
-              logger.info(any(that: stringContainsInOrder(['[!]', 'warning']))),
-        ).called(1);
-
-        verify(
-          () => logger.info(any(that: stringContainsInOrder(['[✗]', 'error']))),
-        ).called(1);
-
-        verify(
-          () => logger.info(any(that: contains('2 issues detected.'))),
-        ).called(1);
+        verify(() => logger.info('  ${yellow.wrap('[!]')} warning')).called(1);
+        verify(() => logger.info('      with multiple lines')).called(1);
+        verify(() => logger.info('  ${red.wrap('[✗]')} error')).called(1);
+        verify(() => logger.info('2 issues detected.')).called(1);
       });
 
       group('when validators only yield warnings', () {