There might be errors in the description of `updateShowCompleted` in codelab

I found two parts of the codelab description that might possibly be errors and report them.

First look at the description in the section on [`Writing data to Proto DataStore`](https://developer.android.com/codelabs/android-proto-datastore#6) in codelab

I'm not sure, but perhaps `userPreferencesStore.updateData()` is correct for the red line in the image, not `dataStore.updateData()`.

##
Second, the sample code in the image above is probably incorrect when the language is not English in codelab.
For example, look at the sample code when the codelab language is Japanese

As well as sample code for the English version,

```
dataStore..updateData { ...
```
The above should be modified as follows
```
userPreferencesStore.updateData { ...
```

Start with the “Writing data to Proto DataStore” section of the linked codelab and compare the English and Japanese rendered examples. Check the updateData receiver shown in each snippet, then verify that both language versions consistently use the intended store reference and render without the duplicated dot.

Written by the indexing model from the issue text.