ln: add udhr_lin_tones source

[moyogo]

udhr_lin is tones less and with 5 vowels, udhr_lin_tones is with tones and 7 vowels.

[r12a]

@moyogo should we just point to udhr_lin_tones, instead (rather than point to both)?

Otherwise, we may need to have 2 entries, since these seem like different orthographies.

[moyogo]

The udhr_lin_tones can be used instead. If you prefer, it fine to have two orthographies as well, one is more academic with 7 vowels with tones optionally marked, used in school books and language learning material, and the second one, with 5 vowels and no tones marked, is vernacular and quite common.