PNG to SVG image's format conversion - references in 'ServerPages.ado…

…c' updated.

Signed-off-by: Dmitri Cherkas <dmitricerkas@yahoo.com>

spec/src/main/asciidoc/ServerPages.adoc

@@ -3679,7 +3679,7 @@ value. If the attribute is not found, `null` is returned.
 
 [[_JSP_Resolver_Hierarchy]]
 .*Figure JSP.2-1* JSP Resolver Hierarchy
-image:sp-2.png[image]
+image:sp-2.svg[image]
 
 === Functions
 
@@ -6175,7 +6175,7 @@ produce responses.
 
 [[_Relationship_between_JSP_Pages_and_XML_views_of_JSP_pages]]
 .*Figure JSP.{jsp-chapter}-1* Relationship between JSP Pages and XML views of JSP pages
-image:sp-4.png[image]
+image:sp-4.svg[image]
 
 JSP documents are used by JSP page authors.
 They can be authored directly, using a text editor, through an XML
@@ -10170,7 +10170,7 @@ the `Servlet` class corresponding to the JSP page must implement the
 
 [[Contracts_between_a_JSP_Page_and_a_JSP_Container]]
 .*Figure JSP.{jsp-chapter}-1* Contracts between a JSP Page and a JSP Container
-image:sp-11.png[image]
+image:sp-11.svg[image]
 
 
 The involved contracts are shown in