Replace base::lambda with shorter term.

base::lambda -> Fn (type alias for std::function).
base::lambda_once -> FnMut (type alias for base::unique_function).
base::lambda_guarded -> crl::guard.
base::lambda_call_type_t -> crl::deduced_call_type.

Telegram/SourceFiles/chat_helpers/emoji_suggestions_widget.cpp

@@ -367,7 +367,7 @@ SuggestionsController::SuggestionsController(QWidget *parent, not_null<QTextEdit
 }
 
 void SuggestionsController::setReplaceCallback(
-	base::lambda<void(
+	Fn<void(
 		int from,
 		int till,
 		const QString &replacement)> callback) {