inhibit change hooks during (insert content)

I reproduced the problem with
```elisp
(progn
  (switch-to-buffer "test.cc")
  (c++-mode)
  (insert "#include <foo>\n")
  (save-restriction
    (narrow-to-region (point) (point))
    (insert "main")))
```

This corresponds to the `(insert content)` in `yas-expand-snippet`.

It's something about the 0 size region that cc-mode doesn't like. I don't understand 100% why this is (`cc-mode` is too complicated for mortals to understand) but inhibiting cc-mode's change hooks solves the issue for me.