Slightly improve consistency of "fooint" vs "foo_int" in DPCPU(9) exa…

…mples.

MFC after:	3 days

share/man/man9/dpcpu.9

@@ -57,20 +57,20 @@ Arbitrary C types may be used, including structures and arrays.
 If no initialization is provided, then each per-CPU instance of the variable
 will be zero-filled (i.e., as though allocated in BSS):
 .Bd -literal -offset 1234
-DPCPU_DEFINE(int, fooint);
+DPCPU_DEFINE(int, foo_int);
 .Ed
 .Pp
 Values may also be initialized statically with the definition, causing each
 per-CPU instance to be initialized with the value:
 .Bd -literal -offset 1234
-DPCPU_DEFINE(int, fooint) = 1;
+DPCPU_DEFINE(int, foo_int) = 1;
 .Ed
 .Pp
 Syntactically, the definition may be treated as a variable.
 For example, a dynamic per-CPU variable may be declared as
 .Dv static :
 .Bd -literal -offset 1234
-static DPCPU_DEFINE(int, fooint);
+static DPCPU_DEFINE(int, foo_int);
 .Ed
 .Pp
 .Fn DPCPU_DECLARE