Update the documentation.

docs/user/appendix_column.rst

@@ -85,7 +85,20 @@ All columns
 
 ``renderer``
     A string pointing to the javascript function rendering the value or
-    containing the function itself. The possible value is ``reprDuration``.
+    containing the function itself. The possible value is ``reprDuration`` or
+    ``(function(value) {Ext.util.Format.number(value, '0.0')})``. In the last
+    syntax, the parenthesis at the beginning and at the end are mandatory.
+
+``summaryRenderer``
+    A string containing the function to render the summary value, *e.g*
+    ``(function(value) {Ext.util.Format.number(value, '0.0')})``. The
+    parenthesis at the beginning and at the end are mandatory.
+    See the documentation for more complex strategy.
+
+``summaryType``
+    Summary are computed over the column values.
+    Possible functions are ``"count"``, ``"sum"``, ``"min"``, ``"max"`` and
+    ``"average"``.
 
 ``text``
     the string containing the label of the column.
@@ -121,11 +134,6 @@ Number column
 ``format``
     the format string, *e.g.* ``"0,000.00"``.
 
-``summaryType``
-    Summary are computed over the column values.
-    Possible functions are ``"count"``, ``"sum"``, ``"min"``, ``"max"`` and
-    ``"average"``.
-
 Row numbered column
 -------------------