refactor: use null-safe annotations where applicable

Author: lppedd

src/main/java/com/github/lppedd/cc/angular2/Angular2CommitScopeProvider.java

@@ -35,7 +35,7 @@ class Angular2CommitScopeProvider implements CommitScopeProvider {
   private static final Application APPLICATION = ApplicationManager.getApplication();
   private final Project project;
 
-  Angular2CommitScopeProvider(final Project project) {
+  Angular2CommitScopeProvider(@NotNull final Project project) {
     this.project = project;
   }
 
@@ -53,7 +53,7 @@ public ProviderPresentation getPresentation() {
 
   @NotNull
   @Override
-  public List<CommitScope> getCommitScopes(final String commitType) {
+  public List<CommitScope> getCommitScopes(@Nullable final String commitType) {
     return "build".equals(commitType) ? SCOPES : findNgModules();
   }
 

src/main/java/com/github/lppedd/cc/angular2/Angular2CommitTypeProvider.java

@@ -40,7 +40,7 @@ public ProviderPresentation getPresentation() {
 
   @NotNull
   @Override
-  public List<CommitType> getCommitTypes(final String prefix) {
+  public List<CommitType> getCommitTypes(@Nullable final String prefix) {
     return TYPES;
   }