Rework translation system to use PO files

The French translations are provided by Tanavit. Unfortunately I was not
able to keep this addition as a separate commit as the translation file
was originally added as a .tr file that I then converted to .po file in
the meantime.

Also note that this commit is created from squashing 20+ commits from
the l10n branch that preceded the transition to PO files. In addition to
changes to the locale files (which were all included in the single
commit for transitioning to PO files), these commits also included code
that has now become obsolete for l10n work. In particular, it included a
GUI program written in Tcl to edit .tr files; this program can now be
found in the following repo: https://codeberg.org/y5nw/mt_tr_editor

Co-authored-by: Tanavit <tanavit@posto.ovh>

1 files changed, 69 insertions, 0 deletions

diff --git a/advtrains/locale/README.md b/advtrains/locale/README.md
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+# Translations
+**Please note that this document is outdated as transition to `.po`
+files is currently in progress.**
+
+Please read this document before working on any translations.
+
+## Getting Started
+If there is a translation file for your language (e.g. German), you can
+edit the file directly. Please read [the documentation on the
+translation file format][tr-format].
+
+Alternatively, Advtrains provides a script named `gui` that can be used
+to, among other things, edit translation files. The script requires
+Tcl/Tk 8.6, which is provided by most Linux distributions.
+
+If the translation file for your language does not exist, create it by
+copying `template.txt` to `advtrains.XX.tr`, where `XX` is replaced by
+the language code.
+
+Feel free to use the [discussion mailing list][srht-discuss] if you
+have any questions regarding localization.
+
+You can share your `.tr` file directly or [as a patch][gsm] to the [dev
+mailing list][srht-devel]. The latter is encouraged, but, unlike code
+changes, translation files sent directly are also accepted.
+
+[tr-format]: https://minetest.gitlab.io/minetest/translations/#translation-file-format
+[srht-discuss]: https://lists.sr.ht/~gpcf/advtrains-discuss
+[srht-devel]: https://lists.sr.ht/~gpcf/advtrains-devel
+[gsm]: https://git-send-email.io
+
+## Translation Notes
+* Translations should be consistent. You can use other entries or the
+translations in Minetest as a reference.
+* Translations do not have to fully correspond to the original text -
+they only need to provide the same information. In particular,
+translations do not need to have the same linguistical structure as the
+original text.
+* Replacement sequences (`@1`, `@2`, etc) should not be translated.
+* Certain abbreviations or names, such as "Ks" or "Zs 3", should
+generally not be translated.
+
+### (de) German
+* Verwenden Sie die neue Rechtschreibung und die Sie-Form.
+* Mit der deutschen Tastaturbelegung unter Linux können die
+Anführungszeichen „“ mit AltGr-V bzw. AltGr-B eingegeben werden.
+
+### (zh) Chinese
+(This section is written in English to avoid writing the note twice or
+using only one of the variants, as most of this section applies to both
+the traditional and simplified variants.)
+
+* Please use the 「」 quotation marks for Traditional Chinese and “”
+for Simplified Chinese.
+* Please use the fullwidth variants of: ， 、 。 ？ ！ ： ；
+* Please use the halfwidth variants of: ( ) [ ] / \ |
+* Please do not leave any space between Han characters (including
+fullwidth punctuation marks).
+* Please leave a space between Han characters (excluding fullwidth
+punctuation marks) and characters from other scripts (including
+halfwidth punctuation marks). However, do not leave any space between
+Han characters and Arabic numerals.
+
+## Notes for developers
+* Avoid word-by-word translations.
+* Avoid manipulating translated strings (except for concatenation). Use
+server-side translations if you have to modify the text sent to users.
+* Avoid truncating strings unless multibyte characters are handled
+properly.