bug#41905: Small change: In Customize, display name with with spaces, but keep symbol name underneath.

[Juri Linkov]

>>> (concat (propertize "f" 'display "F")
>>>         "ill"
>>>         (propertize "-" 'display " ")
>>>         (propertize "c" 'display "C")
>>>         "olumn")
>>
>> Actually I meant not concat, but set-text-properties:
>>
>> (let ((name "fill-column"))
>>  (set-text-properties 0 1 '(display "F") name)
>>  (set-text-properties 4 5 '(display " ") name)
>>  (set-text-properties 5 6 '(display "C") name)
>>  (insert name))
>
> Why not concat?  I think the end result is the same?

No difference, indeed :)  But set-text-properties is cleaner:
we have a string and add properties to it.