Improve consistency of top-level help text (#66748)

packages/flutter_tools/lib/src/commands/assemble.dart

@@ -114,7 +114,7 @@ class AssembleCommand extends FlutterCommand {
   }
 
   @override
-  String get description => 'Assemble and build flutter resources.';
+  String get description => 'Assemble and build Flutter resources.';
 
   @override
   String get name => 'assemble';

packages/flutter_tools/lib/src/commands/attach.dart

@@ -77,7 +77,7 @@ class AttachCommand extends FlutterCommand {
         help: 'The URI at which the observatory is listening.',
       )..addOption(
         'app-id',
-        help: 'The package name (Android) or bundle identifier (iOS) for the application. '
+        help: 'The package name (Android) or bundle identifier (iOS) for the app. '
               'This can be specified to avoid being prompted if multiple observatory ports '
               'are advertised.\n'
               'If you have multiple devices or emulators running, you should include the '
@@ -110,7 +110,7 @@ class AttachCommand extends FlutterCommand {
   final String name = 'attach';
 
   @override
-  final String description = '''Attach to a running application.
+  final String description = '''Attach to a running app.
 
   For attaching to Android or iOS devices, simply using `flutter attach` is
   usually sufficient. The tool will search for a running Flutter app or module,

packages/flutter_tools/lib/src/commands/build.dart

@@ -40,7 +40,7 @@ class BuildCommand extends FlutterCommand {
   final String name = 'build';
 
   @override
-  final String description = 'Flutter build commands.';
+  final String description = 'Build an executable app or install bundle.';
 
   @override
   Future<FlutterCommandResult> runCommand() async => null;

packages/flutter_tools/lib/src/commands/channel.dart

@@ -24,7 +24,7 @@ class ChannelCommand extends FlutterCommand {
   final String name = 'channel';
 
   @override
-  final String description = 'List or switch flutter channels.';
+  final String description = 'List or switch Flutter channels.';
 
   @override
   String get invocation => '${runner.executableName} $name [<channel-name>]';

packages/flutter_tools/lib/src/commands/drive.dart

@@ -130,7 +130,7 @@ class DriveCommand extends RunCommandBase {
   final String name = 'drive';
 
   @override
-  final String description = 'Runs Flutter Driver tests for the current project.';
+  final String description = 'Run integration tests for the project on an attached device or emulator.';
 
   @override
   final List<String> aliases = <String>['driver'];

packages/flutter_tools/lib/src/commands/format.dart

@@ -41,7 +41,7 @@ class FormatCommand extends FlutterCommand {
   List<String> get aliases => const <String>['dartfmt'];
 
   @override
-  final String description = 'Format one or more dart files.';
+  final String description = 'Format one or more Dart files.';
 
   @override
   String get invocation => '${runner.executableName} $name <one or more paths>';

packages/flutter_tools/lib/src/commands/generate_localizations.dart

@@ -155,7 +155,7 @@ class GenerateLocalizationsCommand extends FlutterCommand {
   final FileSystem _fileSystem;
 
   @override
-  String get description => 'Generate localizations for the Flutter project.';
+  String get description => 'Generate localizations for the current project.';
 
   @override
   String get name => 'gen-l10n';

packages/flutter_tools/lib/src/commands/precache.dart

@@ -69,7 +69,7 @@ class PrecacheCommand extends FlutterCommand {
   final String name = 'precache';
 
   @override
-  final String description = "Populates the Flutter tool's cache of binary artifacts.";
+  final String description = "Populate the Flutter tool's cache of binary artifacts.";
 
   @override
   bool get shouldUpdateCache => false;

packages/flutter_tools/lib/src/commands/symbolize.dart

@@ -52,7 +52,7 @@ class SymbolizeCommand extends FlutterCommand {
   final DwarfSymbolizationService _dwarfSymbolizationService;
 
   @override
-  String get description => 'Symbolize a stack trace from an AOT compiled flutter application.';
+  String get description => 'Symbolize a stack trace from an AOT-compiled Flutter app.';
 
   @override
   String get name => 'symbolize';