fix(_tilde): fix false negative with 256 generated users

In the original code, the exit status becomes unexpectedly 0 (True)
when 256 (or multiples of 256) users are generated.  This commit
checks the number of generated users and returns 1 explicitly if there
are one or more users are generated.

Co-authored-by: Ville Skyttä <ville.skytta@iki.fi>

Author: akinomyoga

bash_completion

@@ -1266,8 +1266,8 @@ _ncpus()
 
 # Perform tilde (~) completion
 # @return  True (0) if completion needs further processing,
-#          False (> 0) if tilde is followed by a valid username, completions
-#          are put in COMPREPLY and no further processing is necessary.
+#          False (1) if tilde is followed by a valid username, completions are
+#          put in COMPREPLY and no further processing is necessary.
 _tilde()
 {
     local result=0
@@ -1278,7 +1278,7 @@ _tilde()
         # 2>/dev/null for direct invocation, e.g. in the _tilde unit test
         ((result > 0)) && compopt -o filenames 2>/dev/null
     fi
-    return "$result"
+    return $((result > 0 ? 1 : 0))
 }
 
 # Expand variable starting with tilde (~)