Log Message:
editors/tp-note: update to 1.17.0

Add the user's language tag to new note's header.

This release defines the new template varialbe {{ lang }} which inserts the
user's default language tag, e.g. "lang: en-GB".
The header is understood by the grammar, style & spell checker LanguageTool
(https://languagetool.org/).
If wished for, the user's default languange tag can be overwritten with the
environment variable TPNOTELANG.