better MkConcrete and example in lib/resource/doc/example

lib/resource/doc/example/QuestionsEng.gf

@@ -1,2 +1,2 @@
-concrete QuestionsEng of Questions = QuestionsI with 
+concrete QuestionsEng of Questions = QuestionsExI with 
   (Resource = ResourceEng) ;

lib/resource/doc/example/QuestionsExI.gfe

@@ -0,0 +1,15 @@
+--# -resource=../../langeng.gfcm
+
+-- to compile: gf -makeconcrete QuestionsExI.gfe
+
+incomplete concrete QuestionsExI of Questions = open Resource in {
+  lincat
+    Phrase = Phr ;
+    Entity = N ;
+    Action = V2 ;
+
+  lin Who  love_V2 man_N           = in Phr "who loves the men?" ;
+  lin Whom man_N love_V2           = in Phr "whom does the man love?" ;
+  lin Answer woman_N love_V2 man_N = in Phr "the woman loves the man." ;
+
+}