Add description for the 'll' modifier for long long. In essence a copy

from the 'l' description with s/long/long long/g.

PR:		27017
Submitted by:	Guy Harris <guy@alum.mit.edu>
MFC after:	2 weeks

lib/libc/stdio/printf.3

@@ -139,7 +139,7 @@ to be a pointer to a buffer sufficiently large to hold the formatted string.
 This pointer should be passed to
 .Xr free 3
 to release the allocated storage when it is no longer needed.
-If sufficient space cannot be allocated, 
+If sufficient space cannot be allocated,
 .Fn asprintf
 and
 .Fn vasprintf
@@ -204,7 +204,7 @@ A
 .Cm #
 character
 specifying that the value should be converted to an ``alternate form''.
-For 
+For
 .Cm c ,
 .Cm d ,
 .Cm i ,
@@ -214,7 +214,7 @@ For
 and
 .Cm u ,
 conversions, this option has no effect.
-For 
+For
 .Cm o
 conversions, the precision of the number is increased to force the first
 character of the output string to a zero (except if a zero value is printed
@@ -371,6 +371,26 @@ conversion corresponds to a pointer to a
 .Em long int
 argument.
 .It
+The optional characters
+.Cm ll
+(ell ell) specifying that a following
+.Cm d ,
+.Cm i ,
+.Cm o ,
+.Cm u ,
+.Cm x ,
+or
+.Cm X
+conversion applies to a pointer to a
+.Em long long int
+or
+.Em unsigned long long int
+argument, or that a following
+.Cm n
+conversion corresponds to a pointer to a
+.Em long long int
+argument.
+.It
 The optional character
 .Cm q ,
 specifying that a following
@@ -623,7 +643,7 @@ and
 .Fn vsprintf
 functions
 conform to
-.St -ansiC 
+.St -ansiC
 and
 .St -isoC-99 .
 The