Fix links (#2673)

* fix holoweb link
* update (one of the) doi URL(s) to DOI idno

P5/Source/Guidelines/en/BIB-Bibliography.xml

@@ -1488,7 +1488,7 @@
             <forename>G.</forename>
           </author>
           <title level="a">Colonialism and the Emergence of Racial Theories</title>
-          <ptr target="https://doi.org/10.1017/9781107705647.032"/>
+          <idno type="DOI">10.1017/9781107705647.032</idno>
         </analytic>
         <monogr>
           <title level="m">Reproduction: Antiquity to the Present Day</title>
@@ -4842,7 +4842,7 @@
             </author>
             <title level="a">Suggestive Markup: Explicit Relationships in Descriptive and
               Prescriptive DTDs</title>
-            <ptr target="http://www.holoweb.net/~liam/papers/1996-sgml96-SuggestiveMarkup/"/>
+            <ptr target="https://www.holoweb.net/liam/papers/1996-sgml96-SuggestiveMarkup/"/>
           </analytic>
           <monogr>
             <editor>