Fix swiftformat config: --never-trailing → --nevertrailing

The option name has no hyphen in newer swiftformat versions.

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Co-Authored-By: Claude Opus 4.5 <[email protected]>

Author: kylehowells

.swiftformat

@@ -12,7 +12,7 @@
 
 # Never use trailing closures
 --enable trailingClosures
---never-trailing
+--nevertrailing
 
 # Else on next line
 --enable elseOnSameLine