Fix issues found by mandoc -Tlint.

MFC after:	1 week

share/man/man9/DEVICE_PROBE.9

@@ -100,7 +100,8 @@ This is for source or binary drivers that are not yet integrated into the
 tree.
 Its use in the base OS is prohibited.
 .It BUS_PROBE_DEFAULT
-The device is a normal device matching some plug and play ID.  This is
+The device is a normal device matching some plug and play ID.
+This is
 the normal return value for drivers to use.
 It is intended that nearly all of the drivers in the tree should return
 this value.

share/man/man9/kern_testfrwk.9

@@ -65,7 +65,6 @@ When your test loads, you register your tests with the kernel test framework.
 You do that through a call to
 .Fn kern_testframework_register .
 Usually this is done at the module load event as shown below:
-.Pp
 .Bd -literal -offset indent
 	switch (type) {
 	case MOD_LOAD:
@@ -122,7 +121,6 @@ field is a test-specific set of information that is an opaque blob.
 It is passed in from user space and has a maximum size of 256 bytes.
 You can pass arbitrary test input in the space.
 In the case of callout_test we reshape that to:
-.Pp
 .Bd -literal -offset indent
 struct callout_test {
 	int number_of_callouts;
@@ -133,7 +131,6 @@ struct callout_test {
 So the first lines of
 .Fn run_callout_test
 does the following to get at the user specific data:
-.Pp
 .\" This is a bad example and violates strict aliasing.  It should be replaced.
 .Bd -literal -offset indent
 	struct callout_test *u;

share/man/man9/malloc.9

@@ -229,7 +229,7 @@ may sleep when called with
 never sleeps.
 However,
 .Fn malloc ,
-.Fn realloc,
+.Fn realloc ,
 .Fn reallocf
 and
 .Fn free

share/man/man9/timeout.9

@@ -261,7 +261,7 @@ returns zero it will arrange for the function
 .Fa drain
 to be called using the same argument given to the
 .Fn callout_reset
-function. 
+function.
 .Fn callout_async_drain
 If the callout has an associated lock,
 then that lock must be held when this function is called.