doc: Fix various groff/nroff warnings.

doc/ck_cohort

@@ -188,7 +188,7 @@ main(void)
 
 	return 0;
 }
-
+.Ed
 .Sh SEE ALSO
 .Xr CK_COHORT_PROTOTYPE 3 ,
 .Xr CK_COHORT_TRYLOCK_PROTOTYPE 3 ,

doc/ck_epoch_barrier

@@ -95,6 +95,7 @@ function(void)
 	free(s);
 	return;
 }
+.Ed
 .Sh RETURN VALUES
 This function has no return value.
 .Sh ERRORS

doc/ck_epoch_call

@@ -33,9 +33,7 @@
 Concurrency Kit (libck, \-lck)
 .Sh SYNOPSIS
 .In ck_epoch.h
-
 typedef struct ck_epoch_entry ck_epoch_entry_t;
-
 typedef void ck_epoch_cb_t(ck_epoch_entry_t *);
 .Ft void
 .Fn ck_epoch_call "ck_epoch_t *epoch" "ck_epoch_record_t *record" "ck_epoch_entry_t *entry" "ck_epoch_cb_t *function"
@@ -114,6 +112,7 @@ function(void)
 	ck_epoch_poll(&epoch, record);
 	return;
 }
+.Ed
 .Sh RETURN VALUES
 This function has no return value.
 .Sh ERRORS

doc/ck_epoch_synchronize

@@ -99,6 +99,7 @@ function(void)
 	free(s);
 	return;
 }
+.Ed
 .Sh RETURN VALUES
 This function has no return value.
 .Sh ERRORS

doc/ck_hs_destroy

@@ -43,7 +43,6 @@ function will request that the underlying allocator, as specified by the
 function, immediately destroy the object pointed to by the
 .Fa hs
 argument.
-
 The user must guarantee that no threads are accessing the object pointed to
 by
 .Fa hs

doc/ck_hs_stat

@@ -48,6 +48,7 @@ struct ck_hs_stat {
 	unsigned long n_entries;    /* Current number of keys in hash set. */
 	unsigned int probe_maximum; /* Longest read-side probe sequence. */
 };
+.Ed
 .Sh RETURN VALUES
 .Fn ck_hs_stat 3
 has no return value.