nvim: move ufo plugin spec and utils to its own file.

nvim/lua/user/plugins/editor/ufo.lua

@@ -0,0 +1,35 @@
+return {
+    'kevinhwang91/nvim-ufo',
+    dependencies = {
+        'kevinhwang91/promise-async',
+    },
+    opts = {
+        fold_virt_text_handler = function(virtText, lnum, endLnum, width, truncate)
+            local newVirtText = {}
+            local suffix = (' --- %d '):format(endLnum - lnum)
+            local sufWidth = vim.fn.strdisplaywidth(suffix)
+            local targetWidth = width - sufWidth
+            local curWidth = 0
+            for _, chunk in ipairs(virtText) do
+                local chunkText = chunk[1]
+                local chunkWidth = vim.fn.strdisplaywidth(chunkText)
+                if targetWidth > curWidth + chunkWidth then
+                    table.insert(newVirtText, chunk)
+                else
+                    chunkText = truncate(chunkText, targetWidth - curWidth)
+                    local hlGroup = chunk[2]
+                    table.insert(newVirtText, {chunkText, hlGroup})
+                    chunkWidth = vim.fn.strdisplaywidth(chunkText)
+                    -- str width returned from truncate() may less than 2nd argument, need padding
+                    if curWidth + chunkWidth < targetWidth then
+                        suffix = suffix .. (' '):rep(targetWidth - curWidth - chunkWidth)
+                    end
+                    break
+                end
+                curWidth = curWidth + chunkWidth
+            end
+            table.insert(newVirtText, {suffix, 'MoreMsg'})
+            return newVirtText
+        end
+    }
+}