lua/shared: move table util funcs to vim.shared

Use `tbl_` prefix for all table-util functions. Specify in the function
docstring if it expects a list-like or map-like table.

test/functional/helpers.lua

@@ -15,7 +15,7 @@ local dedent = global_helpers.dedent
 local eq = global_helpers.eq
 local ok = global_helpers.ok
 local sleep = global_helpers.sleep
-local table_contains = global_helpers.table_contains
+local tbl_contains = global_helpers.tbl_contains
 local write_file = global_helpers.write_file
 
 local start_dir = lfs.currentdir()
@@ -165,7 +165,7 @@ local function expect_msg_seq(...)
         error(cat_err(final_error,
                       string.format('got %d messages (ignored %d), expected %d',
                                     #actual_seq, nr_ignored, #expected_seq)))
-      elseif table_contains(ignore, msg_type) then
+      elseif tbl_contains(ignore, msg_type) then
         nr_ignored = nr_ignored + 1
       else
         table.insert(actual_seq, msg)
@@ -339,9 +339,9 @@ local function remove_args(args, args_rm)
   end
   local last = ''
   for _, arg in ipairs(args) do
-    if table_contains(skip_following, last) then
+    if tbl_contains(skip_following, last) then
       last = ''
-    elseif table_contains(args_rm, arg) then
+    elseif tbl_contains(args_rm, arg) then
       last = arg
     else
       table.insert(new_args, arg)

test/functional/options/defaults_spec.lua

@@ -15,7 +15,7 @@ local neq = helpers.neq
 local mkdir = helpers.mkdir
 local rmdir = helpers.rmdir
 local alter_slashes = helpers.alter_slashes
-local table_contains = helpers.table_contains
+local tbl_contains = helpers.tbl_contains
 
 describe('startup defaults', function()
   describe(':filetype', function()
@@ -261,7 +261,7 @@ describe('XDG-based defaults', function()
 
     for _,v in ipairs(rtp) do
       local m = string.match(v, [=[[/\]nvim[^/\]*[/\]site.*$]=])
-      if m and not table_contains(rv, m) then
+      if m and not tbl_contains(rv, m) then
         table.insert(rv, m)
       end
     end