Fix two more regression tests whose expected outputs were not updated

for the recent may/might cleanup.

contrib/dblink/expected/dblink.out

@@ -509,7 +509,7 @@ SELECT dblink_close('myconn','rmt_foo_cursor');
 -- this should fail because there is no open transaction
 SELECT dblink_exec('myconn','DECLARE xact_test CURSOR FOR SELECT * FROM foo');
 ERROR:  sql error
-DETAIL:  ERROR:  DECLARE CURSOR may only be used in transaction blocks
+DETAIL:  ERROR:  DECLARE CURSOR can only be used in transaction blocks
 
 -- reset remote transaction state
 SELECT dblink_exec('myconn','ABORT');

contrib/earthdistance/expected/earthdistance.out

@@ -882,7 +882,7 @@ SELECT is_point(ll_to_earth(0,0));
 ERROR:  function is_point(earth) does not exist
 LINE 1: SELECT is_point(ll_to_earth(0,0));
                ^
-HINT:  No function matches the given name and argument types. You may need to add explicit type casts.
+HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
 SELECT cube_dim(ll_to_earth(0,0)) <= 3;
  ?column? 
 ----------
@@ -900,7 +900,7 @@ SELECT is_point(ll_to_earth(30,60));
 ERROR:  function is_point(earth) does not exist
 LINE 1: SELECT is_point(ll_to_earth(30,60));
                ^
-HINT:  No function matches the given name and argument types. You may need to add explicit type casts.
+HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
 SELECT cube_dim(ll_to_earth(30,60)) <= 3;
  ?column? 
 ----------
@@ -918,7 +918,7 @@ SELECT is_point(ll_to_earth(60,90));
 ERROR:  function is_point(earth) does not exist
 LINE 1: SELECT is_point(ll_to_earth(60,90));
                ^
-HINT:  No function matches the given name and argument types. You may need to add explicit type casts.
+HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
 SELECT cube_dim(ll_to_earth(60,90)) <= 3;
  ?column? 
 ----------
@@ -936,7 +936,7 @@ SELECT is_point(ll_to_earth(-30,-90));
 ERROR:  function is_point(earth) does not exist
 LINE 1: SELECT is_point(ll_to_earth(-30,-90));
                ^
-HINT:  No function matches the given name and argument types. You may need to add explicit type casts.
+HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
 SELECT cube_dim(ll_to_earth(-30,-90)) <= 3;
  ?column? 
 ----------