Update to latest Mylyn Wikitext

It's a major version bump which made too many things internal but that
will be rectified via
eclipse-mylyn/org.eclipse.mylyn#523

org.eclipse.lsp4e/META-INF/MANIFEST.MF

@@ -31,8 +31,8 @@ Require-Bundle: org.eclipse.core.runtime;bundle-version="3.12.0",
  org.eclipse.ui.navigator;bundle-version="3.6.100",
  org.eclipse.lsp4j;bundle-version="[0.22.0,0.23.0)",
  org.eclipse.lsp4j.jsonrpc;bundle-version="[0.22.0,0.23.0)",
- org.eclipse.mylyn.wikitext;bundle-version="3.0.40",
- org.eclipse.mylyn.wikitext.markdown;bundle-version="3.0.40",
+ org.eclipse.mylyn.wikitext;bundle-version="4.2.0",
+ org.eclipse.mylyn.wikitext.markdown;bundle-version="4.2.0",
  org.eclipse.ui.console,
  org.eclipse.ltk.core.refactoring,
  org.eclipse.core.expressions;bundle-version="3.5.0",

target-platforms/target-platform-latest/target-platform-latest.target

@@ -6,7 +6,7 @@
 			<unit id="org.eclipse.mylyn.wikitext" version="0.0.0"/>
 			<unit id="org.eclipse.mylyn.wikitext.markdown" version="0.0.0"/>
 			<unit id="org.eclipse.mylyn.wikitext.markdown.ui" version="0.0.0"/>
-			<repository location="https://download.eclipse.org/mylyn/docs/releases/3.0.48/"/>
+			<repository location="https://download.eclipse.org/mylyn/updates/release/latest/"/>
 		</location>
 		<location includeAllPlatforms="false" includeConfigurePhase="true" includeMode="planner" includeSource="true" type="InstallableUnit">
 			<unit id="org.eclipse.lsp4j" version="0.0.0"/>