Remove unused strings

app/src/main/java/eu/kanade/tachiyomi/ui/category/CategoryActivity.kt

@@ -82,7 +82,7 @@ class CategoryActivity : BaseRxActivity<CategoryPresenter>(), ActionMode.Callbac
         fab.setOnClickListener({ v ->
             MaterialDialog.Builder(this)
                     .title(R.string.action_add_category)
-                    .negativeText(R.string.button_cancel)
+                    .negativeText(android.R.string.cancel)
                     .input(R.string.name, 0, false)
                     { dialog, input -> presenter.createCategory(input.toString()) }
                     .show()
@@ -125,7 +125,7 @@ class CategoryActivity : BaseRxActivity<CategoryPresenter>(), ActionMode.Callbac
     private fun editCategory(category: Category) {
         MaterialDialog.Builder(this)
                 .title(R.string.action_rename_category)
-                .negativeText(R.string.button_cancel)
+                .negativeText(android.R.string.cancel)
                 .onNegative { materialDialog, dialogAction -> destroyActionModeIfNeeded() }
                 .input(getString(R.string.name), category.name, false)
                 { dialog, input -> presenter.renameCategory(category, input.toString()) }

app/src/main/java/eu/kanade/tachiyomi/ui/setting/SettingsAdvancedFragment.kt

@@ -85,8 +85,8 @@ class SettingsAdvancedFragment : SettingsNestedFragment() {
     private fun clearDatabase() {
         MaterialDialog.Builder(activity)
                 .content(R.string.clear_database_confirmation)
-                .positiveText(R.string.button_yes)
-                .negativeText(R.string.button_no)
+                .positiveText(android.R.string.yes)
+                .negativeText(android.R.string.no)
                 .onPositive { dialog, which -> db.deleteMangasNotInLibrary().executeAsBlocking() }
                 .show()
     }

app/src/main/res/values/strings.xml

@@ -51,12 +51,6 @@
     <string name="action_cancel">Cancel</string>
     <string name="action_sort">Sort</string>
 
-    <!-- Buttons -->
-    <string name="button_ok">OK</string>
-    <string name="button_cancel">Cancel</string>
-    <string name="button_yes">Yes</string>
-    <string name="button_no">No</string>
-
     <!-- Operations -->
     <string name="deleting">Deleting…</string>
     <string name="loading">Loading…</string>