type enclosing: fix limit case for small enclosings
type enclosing: fix limit case for small enclosings

the-lambda-church/merlin,dra27/merlin,fxfactorial/merlin,dra27/merlin,rgrinberg/merlin,ocaml/merlin,neojski/merlin,fxfactorial/merlin,fxfactorial/merlin,ocaml/merlin,neojski/merlin,neojski/merlin,haselwarter/merlin,chambart/merlin,rgrinberg/merlin,chambart/merlin,rgrinberg/merlin,dra27/merlin,fxfactorial/merlin,dra27/merlin,the-lambda-church/merlin,haselwarter/merlin,ocaml/merlin,chriskonstad/merlin,the-lambda-church/merlin,neojski/merlin,ocaml/merlin,chambart/merlin,rgrinberg/merlin,chriskonstad/merlin,chambart/merlin,haselwarter/merlin,haselwarter/merlin