Update gitignore template for flutter create (#21192)

* update gitignore template to mirror

* Add a newline to end of doc

* remove Android/ and iOS/ subfolder gitignores

packages/flutter_tools/templates/create/.gitignore.tmpl

+# Miscellaneous
+*.class
+*.lock
+*.log
+*.pyc
+*.swp
 .DS_Store
-.dart_tool/
+.atom/
+.buildlog/
+.history
+.svn/
+
+# IntelliJ related
+*.iml
+*.ipr
+*.iws
+.idea/
+
+# Visual Studio Code related
+.vscode/
 
+# Flutter/Dart/Pub related
+**/doc/api/
+.dart_tool/
+.flutter-plugins
 .packages
+.pub-cache/
 .pub/
-
 build/
 
-.flutter-plugins
+# Android related
+**/android/**/gradle-wrapper.jar
+**/android/.gradle
+**/android/captures/
+**/android/gradlew
+**/android/gradlew.bat
+**/android/local.properties
+**/android/**/GeneratedPluginRegistrant.java
+
+# iOS/XCode related
+**/ios/**/*.mode1v3
+**/ios/**/*.mode2v3
+**/ios/**/*.moved-aside
+**/ios/**/*.pbxuser
+**/ios/**/*.perspectivev3
+**/ios/**/*sync/
+**/ios/**/.sconsign.dblite
+**/ios/**/.tags*
+**/ios/**/.vagrant/
+**/ios/**/DerivedData/
+**/ios/**/Icon?
+**/ios/**/Pods/
+**/ios/**/.symlinks/
+**/ios/**/profile
+**/ios/**/xcuserdata
+**/ios/.generated/
+**/ios/Flutter/App.framework
+**/ios/Flutter/Flutter.framework
+**/ios/Flutter/Generated.xcconfig
+**/ios/Flutter/app.flx
+**/ios/Flutter/app.zip
+**/ios/Flutter/flutter_assets/
+**/ios/ServiceDefinitions.json
+**/ios/Runner/GeneratedPluginRegistrant.*
+
+# Exceptions to above rules.
+!**/ios/**/default.mode1v3
+!**/ios/**/default.mode2v3
+!**/ios/**/default.pbxuser
+!**/ios/**/default.perspectivev3
+!/packages/flutter_tools/test/data/dart_dependencies_test/**/.packages

packages/flutter_tools/templates/create/android.tmpl/.gitignore

-*.iml
-*.class
-.gradle
-/local.properties
-/.idea/workspace.xml
-/.idea/libraries
-.DS_Store
-/build
-/captures
-GeneratedPluginRegistrant.java

packages/flutter_tools/templates/create/ios.tmpl/.gitignore

-.idea/
-.vagrant/
-.sconsign.dblite
-.svn/
-
-.DS_Store
-*.swp
-profile
-
-DerivedData/
-build/
-GeneratedPluginRegistrant.h
-GeneratedPluginRegistrant.m
-
-.generated/
-
-*.pbxuser
-*.mode1v3
-*.mode2v3
-*.perspectivev3
-
-!default.pbxuser
-!default.mode1v3
-!default.mode2v3
-!default.perspectivev3
-
-xcuserdata
-
-*.moved-aside
-
-*.pyc
-*sync/
-Icon?
-.tags*
-
-/Flutter/app.flx
-/Flutter/app.zip
-/Flutter/flutter_assets/
-/Flutter/App.framework
-/Flutter/Flutter.framework
-/Flutter/Generated.xcconfig
-/ServiceDefinitions.json
-
-Pods/
-.symlinks/