Cleanup for find_keywords.

src/tools/SQL_keywords

@@ -79,7 +79,7 @@ except
 exception
 exec
 execute
-eists
+exists
 external
 extract
 false

src/tools/make_keywords.README

@@ -2,4 +2,8 @@ To get a list of keywords compared to SQL'92, take the keywords out of
 backend/parser/keywords.c and tools/SQL_keywords.
 
 Then run sdif with the PostgreSQL keyword file first, then the SQL'92
-keywords.
+keywords.  Here is what I used:
+
+sdif tools/SQL_keywords /tmp/pgkeywords |\
+sed 's/</ /' | sed 's/>/ /'|sed 's/|/\
+                                        /' | sort -b +0