Allow `find-replace:select-next` to select more occurrences after wrap

The initial position for the search is defined by the last selection 
towards the end of the file.
After reaching the end of the file, it would always select the same 
selection to start the search from.

Now, we start the search from each selection, until a new occurrence is 
found.

data/core/commands/findreplace.lua

@@ -126,6 +126,20 @@ local function has_unique_selection()
   return text ~= nil
 end
 
+local function is_in_selection(line, col, l1, c1, l2, c2)
+  if line < l1 or line > l2 then return false end
+  if line == l1 and col <= c1 then return false end
+  if line == l2 and col > c2 then return false end
+  return true
+end
+
+local function is_in_any_selection(line, col)
+  for idx, l1, c1, l2, c2 in doc():get_selections(true, false) do
+    if is_in_selection(line, col, l1, c1, l2, c2) then return true end
+  end
+  return false
+end
+
 local function select_next(all)
   local il1, ic1 = doc():get_selection(true)
   for idx, l1, c1, l2, c2 in doc():get_selections(true, true) do
@@ -133,9 +147,15 @@ local function select_next(all)
     repeat
       l1, c1, l2, c2 = search.find(doc(), l2, c2, text, { wrap = true })
       if l1 == il1 and c1 == ic1 then break end
-      if l2 then doc():add_selection(l2, c2, l1, c1) end
+      if l2 and (all or not is_in_any_selection(l2, c2)) then
+        doc():add_selection(l2, c2, l1, c1)
+        if not all then
+          core.active_view:scroll_to_make_visible(l2, c2)
+          return
+        end
+      end
     until not all or not l2
-    break
+    if all then break end
   end
 end