HTML formatter doesn't include trailing newlines in spans of class "go", Generic.Output

Lexer "console" assigns class go: Generic.Output to lines that correspond to the output of commands.
For example

$ grep Generic.Output tests/snippets/console/prompt_in_output.txt
'line1\n'     Generic.Output
'> file content, not prompt!\n' Generic.Output

However, the HTML formatter first ends a span of class go, then adds the line separator.

<div class="highlight"><pre><span></span><span class="gp gp-VirtualEnv">(venv) </span><span class="gp">user:~$ </span>ssh-keygen
<span class="go">Generating public/private rsa key pair.</span>
<span class="go">[...]</span>
</pre></div>

This is problematic, because even though one can assign CSS properties to the go class, they will not have an effect on the actual line changes. For example, even when I assign user-select: none to class go, the user can still select and copy stray newlines between consecutive output lines, i.e., between consecutive spans.

Given that the lexer originally assigns Generic.Output to the whole line, including the newline character at the end, we can fix this by extending the line separator into the span itself, so the output becomes:

<div class="highlight"><pre><span></span><span class="gp gp-VirtualEnv">(venv) </span><span class="gp">user:~$ </span>ssh-keygen
<span class="go">Generating public/private rsa key pair.
</span><span class="go">[...]
</span></pre></div>

This does allow the attributes for class go to also extend to the newline characters, and makes things more predictable.

Looking forward to your feedback, I can follow up with a PR that implements this behavior.

Start with the console lexer, the HTML formatter, and the example in tests/snippets/console/prompt_in_output.txt. Trace how Generic.Output line separators are emitted and verify the generated HTML keeps each trailing newline inside its go span, as shown in the issue.