util: fix no-op bug in String.withNonBreakingSpaces()

[RubenKelevra]

Replace(' ', ' ') was replacing regular spaces with regular spaces.
Changed to replace(' ', '\u00A0') so it exchanges spaces to correct non-breaking space character.

[westnordost]

Are you sure? Maybe the no break space was just not displaying? But, no matter, your change makes it clearer regardless

[RubenKelevra]

Yeah I'm sure:

hexdump -C app/src/androidMain/kotlin/de/westnordost/streetcomplete/util/NameAndLocationLabel.kt | grep -A2 -B2 "replace"
00001e30  66 75 6e 20 53 74 72 69  6e 67 2e 69 6e 49 74 61  |fun String.inIta|
00001e40  6c 69 63 73 28 29 3a 20  53 74 72 69 6e 67 20 3d  |lics(): String =|
00001e50  20 22 3c 69 3e 24 7b 72  65 70 6c 61 63 65 48 74  | "<i>${replaceHt|
00001e60  6d 6c 45 6e 74 69 74 69  65 73 28 29 7d 3c 2f 69  |mlEntities()}</i|
00001e70  3e 22 0a 0a 70 72 69 76  61 74 65 20 66 75 6e 20  |>"..private fun |
00001e80  53 74 72 69 6e 67 2e 77  69 74 68 4e 6f 6e 42 72  |String.withNonBr|
00001e90  65 61 6b 69 6e 67 53 70  61 63 65 73 28 29 3a 20  |eakingSpaces(): |
00001ea0  53 74 72 69 6e 67 20 3d  20 72 65 70 6c 61 63 65  |String = replace|
00001eb0  28 27 20 27 2c 20 27 20  27 29 0a                 |(' ', ' ').|
00001ebb