refactor(git): extract util.split_lines helper

lua/util.lua

@@ -428,4 +428,17 @@ function M.get_hl_source(name)
     return hl
 end
 
+---Split a string on newlines, dropping the trailing empty element that an
+---input ending in `\n` produces. Convenient for slicing subprocess stdout
+---into a list of lines without a phantom blank at the end.
+---@param content string
+---@return string[]
+function M.split_lines(content)
+    local lines = vim.split(content, "\n", { plain = true, trimempty = false })
+    if #lines > 0 and lines[#lines] == "" then
+        table.remove(lines)
+    end
+    return lines
+end
+
 return M