patch 8.2.4594: need to write script to a file to be able to source them

Problem:    Need to write script to a file to be able to source them.
Solution:   Make ":source" use lines from the current buffer. (Yegappan
            Lakshmanan et al., closes #9967)
diff --git a/src/ex_cmds.h b/src/ex_cmds.h
index a13de4d..c8ebcf6 100644
--- a/src/ex_cmds.h
+++ b/src/ex_cmds.h
@@ -1428,8 +1428,8 @@
 	EX_RANGE|EX_ZEROR|EX_EXTRA|EX_TRLBAR|EX_NOTRLCOM|EX_CTRLV|EX_CMDWIN|EX_LOCK_OK,
 	ADDR_OTHER),
 EXCMD(CMD_source,	"source",	ex_source,
-	EX_BANG|EX_FILE1|EX_TRLBAR|EX_SBOXOK|EX_CMDWIN|EX_LOCK_OK,
-	ADDR_NONE),
+	EX_RANGE|EX_DFLALL|EX_BANG|EX_FILE1|EX_TRLBAR|EX_SBOXOK|EX_CMDWIN|EX_LOCK_OK,
+	ADDR_LINES),
 EXCMD(CMD_sort,		"sort",		ex_sort,
 	EX_RANGE|EX_DFLALL|EX_WHOLEFOLD|EX_BANG|EX_EXTRA|EX_NOTRLCOM|EX_MODIFY,
 	ADDR_LINES),