Merge #3920

3920: Add chuvash and greek into language index r=def- a=TsFreddie

Both look ok ingame.

## Checklist

- [x] Tested the change ingame
- [ ] Provided screenshots if it is a visual change
- [ ] Tested in combination with possibly related configuration options
- [ ] Written a unit test if it works standalone, system.c especially
- [ ] Considered possible null pointers and out of bounds array indexing
- [ ] Changed no physics that affect existing maps
- [ ] Tested the change with [ASan+UBSan or valgrind's memcheck](https://github.com/ddnet/ddnet/#using-addresssanitizer--undefinedbehavioursanitizer-or-valgrinds-memcheck) (optional)


Co-authored-by: Freddie Wang <tsfreddiewang@gmail.com>

data/languages/index.txt

@@ -24,6 +24,10 @@ catalan
 == Català
 == 906
 
+chuvash
+== Чăвашла
+== 643
+
 czech
 == Česky
 == 203
@@ -48,6 +52,10 @@ german
 == Deutsch
 == 276
 
+greek
+== Ελληνικά
+== 300
+
 hungarian
 == Magyar
 == 348