Placeholder configurers allow for trimming of property values

Issue: SPR-5839

spring-context/src/main/resources/org/springframework/context/config/spring-context-4.3.xsd

@@ -149,6 +149,14 @@
 							<xsd:documentation><![CDATA[
 	The separating character between the placeholder variable and the associated
 	default value: by default, a ':' symbol.
+				]]></xsd:documentation>
+						</xsd:annotation>
+					</xsd:attribute>
+					<xsd:attribute name="trim-values">
+						<xsd:annotation>
+							<xsd:documentation><![CDATA[
+	Whether to trim resolved values before applying them, removing superfluous
+	whitespace (in particular tab characters) from the beginning and end.
 				]]></xsd:documentation>
 						</xsd:annotation>
 					</xsd:attribute>