chore: move help rendering in its own file

lua/nvim-tree/renderer/help.lua

@@ -0,0 +1,52 @@
+local view = require'nvim-tree.view'
+local M = {}
+
+function M.compute_lines()
+  local help_lines = {'HELP'}
+  local help_hl = {{'NvimTreeRootFolder', 0, 0, #help_lines[1]}}
+  local mappings = vim.tbl_filter(function(v)
+    return v.cb ~= nil and v.cb ~= ""
+  end, view.View.mappings)
+  local processed = {}
+  for _, b in pairs(mappings) do
+    local cb = b.cb
+    local key = b.key
+    local name
+    if cb:sub(1,35) == view.nvim_tree_callback('test'):sub(1,35) then
+      name = cb:match("'[^']+'[^']*$")
+      name = name:match("'[^']+'")
+      table.insert(processed, {key, name, true})
+    else
+      name = (b.name ~= nil) and b.name or cb
+      name = '"' .. name .. '"'
+      table.insert(processed, {key, name, false})
+    end
+  end
+  table.sort(processed, function(a,b)
+    return (a[3] == b[3]
+      and (a[2] < b[2] or (a[2] == b[2] and #a[1] < #b[1])))
+      or (a[3] and not b[3])
+  end)
+
+  local num = 0
+  for _, val in pairs(processed) do
+    local keys = type(val[1]) == "string" and {val[1]} or val[1]
+    local map_name = val[2]
+    local builtin = val[3]
+    for _, key in pairs(keys) do
+      num = num + 1
+      local bind_string = string.format("%6s : %s", key, map_name)
+      table.insert(help_lines, bind_string)
+
+      local hl_len = math.max(6, string.len(key)) + 2
+      table.insert(help_hl, {'NvimTreeFolderName', num, 0, hl_len})
+
+      if not builtin then
+        table.insert(help_hl, {'NvimTreeFileRenamed', num, hl_len, -1})
+      end
+    end
+  end
+  return help_lines, help_hl
+end
+
+return M