This is an interesting typo in the 1953 RLDS edition that is apparently the result of adding footnotes to that edition. In this instance, the number 1 was placed as a superscript right before the word city but was apparently written out as one in the 1953 typesetter’s copytext. The result was that the 1953 typesetter added the word one as well as the superscript 1 in the last line of type for verse 150 in chapter XXVI (following the RLDS chapter and versification system):
they took no thought concerning the one 1city of Manti.
(At the bottom of the page, footnote 1 refers the reader to “Verse 134”.) Of course, there are no examples in the Book of Mormon text of “the one city of X”.
Summary: Retain in Alma 58:25 the original phraseology “the city of Manti”.