docs: mention new features in v15, fix 32-bit text again

docs/release_notes.rst

@@ -42,10 +42,10 @@ v15.0.0
 -  Dropped support for Python 3.8.
 -  Dropped support many older dependencies - see ``pyproject.toml`` for details.
    Generally speaking, Ubuntu 22.04 is our baseline system.
--  Dropped support for 32-bit Linux wheels. You must use a 64-bit operating system,
-   and 64-bit versions of Python, Tesseract and Ghostscript to use OCRmyPDF. Many of
-   our dependencies are dropping 32-bit builds (e.g. Pillow), and we are following
-   suit. (Maintainers may still build 32-bit versions from source.)
+-  Dropped support for 32-bit Linux wheels. We strongly recommend a 64-bit operating
+   system, and 64-bit versions of Python, Tesseract and Ghostscript to use OCRmyPDF.
+   Many of our dependencies are dropping 32-bit builds (e.g. Pillow), and we are
+   following suit. (Maintainers may still build 32-bit versions from source.)
 -  Changed to trusted release for PyPI publishing.
 -  pikepdf memory mapping is enabled again for improved performance, now an issue
    with pikepdf has been fixed.
@@ -60,7 +60,10 @@ v15.0.0
    each feature occupies. Typically, small areas of high resolution in PDFs are
    errors or quirks from the repeated use of assets and high resolution is not
    beneficial. :issue:`1010,1104,1004,1079,1010`
--  Ghostscript color conversion strategy is now configurable. :issue:`1143`
+-  Ghostscript color conversion strategy is now configurable using
+   ``--color-conversion-strategy``. :issue:`1143`
+-  JBIG2 threshold for optimization is now configurable using
+   ``--jbig2-threshold``. :issue:`1133`
 
 v14.4.0
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