commands: Rename --i18n-warnings to printI18nWarnings

To get it in line with the others.

docs/content/en/commands/hugo_new.md

@@ -39,7 +39,6 @@ hugo new [path] [flags]
       --forceSyncStatic        copy all files when static is changed.
       --gc                     enable to run some cleanup tasks (remove unused cache files) after the build
   -h, --help                   help for new
-      --i18n-warnings          print missing translations
       --ignoreCache            ignores the cache directory
   -k, --kind string            content type to create
   -l, --layoutDir string       filesystem path to layout directory
@@ -48,6 +47,7 @@ hugo new [path] [flags]
       --noTimes                don't sync modification time of files
       --panicOnWarning         panic on first WARNING log
       --poll string            set this to a poll interval, e.g --poll 700ms, to use a poll based approach to watch for file system changes
+      --printI18nWarnings      print missing translations
       --printMemoryUsage       print memory usage to screen at intervals
       --printPathWarnings      print warnings on duplicate target paths etc.
       --templateMetrics        display metrics about template executions