all: rename the gioui.org/ui module to gioui.org

The "ui" is redundant and stutters.

Signed-off-by: Elias Naur <mail@eliasnaur.com>

app/datadir.go

@@ -0,0 +1,11 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+// +build !android,go1.13
+
+package app
+
+import "os"
+
+func dataDir() (string, error) {
+	return os.UserConfigDir()
+}