Minor doc tweak: replace a "--" with "—".

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index d22f4f4fcd026cbc9727efb5aed6e09bc32b9f17..e89af47a03dd8cd7d61d73ae71037dff2b91aa1d 100644 (file)
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -34,7 +34,7 @@
    A table in a relational database is much like a table on paper: It
    consists of rows and columns.  The number and order of the columns
    is fixed, and each column has a name.  The number of rows is
-   variable -- it reflects how much data is stored at a given moment.
+   variable — it reflects how much data is stored at a given moment.
    SQL does not make any guarantees about the order of the rows in a
    table.  When a table is read, the rows will appear in random order,
    unless sorting is explicitly requested.  This is covered in <xref