RNAProduct: mark genomic_start() and genomic_end() stable

Having carefully analysed miRBase data for mature microRNA products
corresponding to stem-loop sequences already present in Ensembl, I
confirm that the calculation of their start and end in genomic
coordinates is indeed correct for when the stem loop originates from
both forward and reverse strand.

modules/Bio/EnsEMBL/RNAProduct.pm

@@ -306,7 +306,7 @@ sub end {
     Return type : Integer
     Exceptions  : None
     Caller      : General
-    Status      : At Risk (Under Development)
+    Status      : Stable
 
 =cut
 
@@ -338,7 +338,7 @@ sub genomic_end {
     Return type : Integer
     Exceptions  : None
     Caller      : General
-    Status      : At Risk (Under Development)
+    Status      : Stable
 
 =cut