It is a common need to print a "name" of a function or variable like: `hello(name:)`, we should add a helper on DeclSyntax for this See also: https://github.com/apple/swift-syntax/pull/1554/files#diff-9e8c10bde67713af07967e359f29218f8d475994f8618f07c6d7584db7ef1ca9R65-R77