contrib: android: make_apk.sh: add/update testnet comments

Author: Aaron Fiore

contrib/android/make_apk.sh

@@ -34,12 +34,21 @@ info "apk building phase starts."
 # Uncomment and change below to set a custom android package id,
 # e.g. to allow simultaneous mainnet and testnet installs of the apk.
 # defaults:
+#
 #   export APP_PACKAGE_NAME=Electrum
 #   export APP_PACKAGE_DOMAIN=org.electrum
-# FIXME: changing "APP_PACKAGE_NAME" seems to require a clean rebuild of ".buildozer/",
-#        to avoid that, maybe change "APP_PACKAGE_DOMAIN" instead.
-# So, in particular, to build a testnet apk, simply uncomment:
+#
+# FIXME: changing "APP_PACKAGE_NAME" seems to require a clean rebuild of ".buildozer/".
+#        However, even with a clean build, the build appears to break in the final stages (~4.7.0).
+#        To avoid these issues; only change "APP_PACKAGE_DOMAIN" instead.
+#
+# So, in particular, to build testnet APKs, simply uncomment one of the following at a time (per-build):
+#
+# Testnet3
 #export APP_PACKAGE_DOMAIN=org.electrum.testnet
+#
+# Testnet4
+#export APP_PACKAGE_DOMAIN=org.electrum.testnet4
 
 if [ $CI ]; then
     # override log level specified in buildozer.spec to "debug":