top: tweaked the recently introduced 'STARTED' support

When the 'STARTED' field was added, the width was made
the same as the 'TIME+' field. Thus, a full time could
be shown (which then included hundredths of a second).

That kind of granularity is totally unnecessary. After
all, this column is potentially confusing enough since
it is so counterintuitive. So, this commit will reduce
the width of the field with some help from scale_tics.

Henceforth it will not include those ol' centiseconds.

[ along the way let's expand the man document with a ]
[ a remainder about content representation & scaling ]

Reference(s):
. introduced 'start time' field
commit 7647e96b0a

Signed-off-by: Jim Warner <james.warner@comcast.net>

top/top_nls.c

@@ -350,7 +350,7 @@ static void build_two_nlstabs (void) {
 /* Translation Hint: maximum 'AGNI' = 4 */
    Head_nlstab[EU_AGN] = _("AGNI");
    Desc_nlstab[EU_AGN] = _("Autogroup Nice Value");
-/* Translation Hint: maximum 'STARTED' = 9 */
+/* Translation Hint: maximum 'STARTED' = 7 */
    Head_nlstab[EU_TM3] = _("STARTED");
    Desc_nlstab[EU_TM3] = _("Start Time from boot");
 /* Translation Hint: maximum '%CUU' = 6 */