fix(staging): syntax highlighting for ambiguous, not loaded files

lua/tinygit/commands/staging/telescope.lua

@@ -87,11 +87,15 @@ local function getFiletype(absPath)
 	local ft = vim.filetype.match { filename = vim.fs.basename(absPath) }
 	if ft then return ft end
 
-	-- In some cases, the filename alone is not unambiguous(like `.ts` files for
+	-- In some cases, the filename alone is not unambiguous (like `.ts` files for
 	-- typescript), so we need the actual buffer to determine the filetype.
 	local bufnr = vim.iter(vim.api.nvim_list_bufs())
 		:find(function(buf) return vim.api.nvim_buf_get_name(buf) == absPath end)
-	if not bufnr then return nil end
+	if bufnr then return vim.filetype.match { buf = bufnr } end
+
+	-- If there are changes in files that are not loaded as buffer, we have to
+	-- add file to a buffer to be able to determine the filetype from it.
+	bufnr = vim.fn.bufadd(absPath)
 	return vim.filetype.match { buf = bufnr }
 end