Ensure valid whitespace is not trimmed when html parsing mode is used

[rh101]

Describe your changes

Consider the following input:

<p>This is a sentence with a link        <a href="">Click me</a>&nbsp;and      some more text.</p>

or

<p>This is a sentence with a link&nbsp;<a href="">Click me</a>&nbsp;and some more text.</p>

The correct output should be:

This is a sentence with a link Click me and some more text.

What is actually being produced is the following:

This is a sentence with a linkClick meand some more text.

This is only an issue now that the leading and trailing whitespace trimming is enabled, but only affects HTML style parsing, since HTML has   and  , which both insert spaces into the text. Those spaces end up being trimmed, when they should not be.

The fix in this PR will only disable trailing whitespace trimming if and only if html mode is enabled, so it will not have any affect in any other scenario. This fixes the issue with   and  , ensuring the spaces generated by them are part of the output.

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