Improve wording of some pg_upgrade failure reports.

Don't advocate dropping a whole table when dropping a column would
serve.  While at it, try to make the layout of these messages a
bit cleaner and more consistent.

Per suggestion from Daniel Gustafsson.  No back-patch, as we generally
don't like to churn translatable messages in released branches.

Discussion: https://postgr.es/m/2798740.1619622555@sss.pgh.pa.us

src/bin/pg_upgrade/check.c

@@ -1153,8 +1153,8 @@ check_for_reg_data_type_usage(ClusterInfo *cluster)
 		pg_fatal("Your installation contains one of the reg* data types in user tables.\n"
 				 "These data types reference system OIDs that are not preserved by\n"
 				 "pg_upgrade, so this cluster cannot currently be upgraded.  You can\n"
-				 "remove the problem tables and restart the upgrade.  A list of the\n"
-				 "problem columns is in the file:\n"
+				 "drop the problem columns and restart the upgrade.\n"
+				 "A list of the problem columns is in the file:\n"
 				 "    %s\n\n", output_path);
 	}
 	else
@@ -1181,9 +1181,9 @@ check_for_jsonb_9_4_usage(ClusterInfo *cluster)
 		pg_log(PG_REPORT, "fatal\n");
 		pg_fatal("Your installation contains the \"jsonb\" data type in user tables.\n"
 				 "The internal format of \"jsonb\" changed during 9.4 beta so this\n"
-				 "cluster cannot currently be upgraded.  You can remove the problem\n"
-				 "tables and restart the upgrade.  A list of the problem columns is\n"
-				 "in the file:\n"
+				 "cluster cannot currently be upgraded.  You can\n"
+				 "drop the problem columns and restart the upgrade.\n"
+				 "A list of the problem columns is in the file:\n"
 				 "    %s\n\n", output_path);
 	}
 	else

src/bin/pg_upgrade/version.c

@@ -276,11 +276,12 @@ old_9_3_check_for_line_data_type_usage(ClusterInfo *cluster)
 	if (check_for_data_type_usage(cluster, "pg_catalog.line", output_path))
 	{
 		pg_log(PG_REPORT, "fatal\n");
-		pg_fatal("Your installation contains the \"line\" data type in user tables.  This\n"
-				 "data type changed its internal and input/output format between your old\n"
-				 "and new clusters so this cluster cannot currently be upgraded.  You can\n"
-				 "remove the problem tables and restart the upgrade.  A list of the problem\n"
-				 "columns is in the file:\n"
+		pg_fatal("Your installation contains the \"line\" data type in user tables.\n"
+				 "This data type changed its internal and input/output format\n"
+				 "between your old and new versions so this\n"
+				 "cluster cannot currently be upgraded.  You can\n"
+				 "drop the problem columns and restart the upgrade.\n"
+				 "A list of the problem columns is in the file:\n"
 				 "    %s\n\n", output_path);
 	}
 	else
@@ -313,9 +314,10 @@ old_9_6_check_for_unknown_data_type_usage(ClusterInfo *cluster)
 	if (check_for_data_type_usage(cluster, "pg_catalog.unknown", output_path))
 	{
 		pg_log(PG_REPORT, "fatal\n");
-		pg_fatal("Your installation contains the \"unknown\" data type in user tables.  This\n"
-				 "data type is no longer allowed in tables, so this cluster cannot currently\n"
-				 "be upgraded.  You can remove the problem tables and restart the upgrade.\n"
+		pg_fatal("Your installation contains the \"unknown\" data type in user tables.\n"
+				 "This data type is no longer allowed in tables, so this\n"
+				 "cluster cannot currently be upgraded.  You can\n"
+				 "drop the problem columns and restart the upgrade.\n"
 				 "A list of the problem columns is in the file:\n"
 				 "    %s\n\n", output_path);
 	}
@@ -456,10 +458,10 @@ old_11_check_for_sql_identifier_data_type_usage(ClusterInfo *cluster)
 								  output_path))
 	{
 		pg_log(PG_REPORT, "fatal\n");
-		pg_fatal("Your installation contains the \"sql_identifier\" data type in user tables\n"
-				 "and/or indexes.  The on-disk format for this data type has changed, so this\n"
-				 "cluster cannot currently be upgraded.  You can remove the problem tables or\n"
-				 "change the data type to \"name\" and restart the upgrade.\n"
+		pg_fatal("Your installation contains the \"sql_identifier\" data type in user tables.\n"
+				 "The on-disk format for this data type has changed, so this\n"
+				 "cluster cannot currently be upgraded.  You can\n"
+				 "drop the problem columns and restart the upgrade.\n"
 				 "A list of the problem columns is in the file:\n"
 				 "    %s\n\n", output_path);
 	}