(sql-product-alist): Add :name tag to entries.

(sql-product-alist): Add :name tag to entries.
(sql-product): Use it.
(sql-mode-menu): Auto-generate the menu based on sql-product-alist.
(sql-set-product): Add completion.
(sql-highlight-oracle-keywords, sql-highlight-postgres-keywords)
(sql-highlight-linter-keywords, sql-highlight-ms-keywords)
(sql-highlight-ansi-keywords, sql-highlight-sybase-keywords)
(sql-highlight-informix-keywords, sql-highlight-interbase-keywords)
(sql-highlight-ingres-keywords, sql-highlight-solid-keywords)
(sql-highlight-mysql-keywords, sql-highlight-sqlite-keywords)
(sql-highlight-db2-keywords): Remove.
(sql-find-sqli-buffer, sql-set-sqli-buffer-generally)
(sql-highlight-product): Use derived-mode-p.
(sql-set-sqli-buffer): Use with-current-buffer.
(sql-connect-informix, sql-connect-ingres, sql-connect-oracle): Simplify.