fix pkg typos (#82544)

packages/flutter_tools/lib/src/base/user_messages.dart

@@ -226,7 +226,7 @@ class UserMessages {
       'can be downloaded from https://github.com/ninja-build/ninja/releases';
   String ninjaTooOld(String minimumVersion) => 'ninja $minimumVersion or later is required.';
   String pkgConfigVersion(String version) => 'pkg-config version $version';
-  String get pkgConfigMissing => 'pgk-config is required for Linux development.\n'
+  String get pkgConfigMissing => 'pkg-config is required for Linux development.\n'
       'It is likely available from your distribution (e.g.: apt install pkg-config), or '
       'can be downloaded from https://www.freedesktop.org/wiki/Software/pkg-config/';
   String pkgConfigTooOld(String minimumVersion) => 'pkg-config $minimumVersion or later is required.';

packages/flutter_tools/test/general.shard/linux/linux_doctor_test.dart

@@ -45,7 +45,7 @@ FakeCommand _ninjaPresentCommand(String version) {
   );
 }
 
-// A command that will return typical-looking 'pgk-config --version' output with
+// A command that will return typical-looking 'pkg-config --version' output with
 // the given version number.
 FakeCommand _pkgConfigPresentCommand(String version) {
   return FakeCommand(