Lua: add methods `insert`, `remove`, and `sort` to pandoc.List

The functions `table.insert`, `table.remove`, and `table.sort` are added
to pandoc.List elements.  They can be used as methods, e.g.

    local numbers = pandoc.List {2, 3, 1}
    numbers:sort()     -- numbers is now {1, 2, 3}

1 files changed, 17 insertions, 0 deletions

diff --git a/data/pandoc.List.lua b/data/pandoc.List.lua
index f5b118965..b33c30876 100644
--- a/data/pandoc.List.lua
+++ b/data/pandoc.List.lua
@@ -104,6 +104,12 @@ function List:includes (needle, init)
   return not (List.find(self, needle, init) == nil)
 end
 
+--- Insert an element into the list. Alias for `table.insert`.
+-- @param list list
+-- @param[opt] pos position at which the new element is to be inserted
+-- @param value value to insert
+List.insert = table.insert
+
 --- Returns a copy of the current list by applying the given function to
 -- all elements.
 -- @param fn function which is applied to all list items.
@@ -115,6 +121,17 @@ function List:map (fn)
   return res
 end
 
+--- Remove element from list (alias for `table.remove`)
+-- @param list list
+-- @param[opt] pos position of the element to be removed (default: #list)
+-- @return the removed element
+List.remove = table.remove
+
+--- Sort list in-place (alias for `table.sort`)
+-- @param list list
+-- @param[opt] comp comparison function; default to `<` operator.
+List.sort = table.sort
+
 -- Set metatable with __call metamethod. This allows the use of `List`
 -- as a constructor function.
 local ListMT = {