Doc: Fix typo in DiffTextWidget code sample

[DesignThinkerer]

Add missing " in the code block :

From this:

<$diff-text source="This is the original text" dest="This is the text to compare to" mode="words>
    These are the <<diff-count>> differences:
</$diff-text>

To this:

<$diff-text source="This is the original text" dest="This is the text to compare to" mode="words">
    These are the <<diff-count>> differences:
</$diff-text>

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✅ Change Note Status

This PR contains documentation or configuration changes that typically don't require a change note.

[pmario]

for types like this one, we do not change the modified timestamp

[DesignThinkerer]

ok, I reverted to the previous modified timestamp :)