fix: removed non-existent src directory from documentation plugin

This only fixes the issue in the Eclipse project files. If they are
re-generated from the pom.xml this problem will occur again.
diff --git a/org.eclipse.capra.documentation/.classpath b/org.eclipse.capra.documentation/.classpath
index 22f3064..075009d 100644
--- a/org.eclipse.capra.documentation/.classpath
+++ b/org.eclipse.capra.documentation/.classpath
@@ -1,6 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <classpath>
-	<classpathentry kind="src" path="src"/>
 	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.8"/>
 	<classpathentry kind="con" path="org.eclipse.pde.core.requiredPlugins"/>
 	<classpathentry kind="output" path="bin"/>