Bumping required Python version to v3.9 + adding new Polyfills for IDEs.

LogarithmPlotter/qml/eu/ad5001/LogarithmPlotter/js/lib/qmlpolyfills.mjs

@@ -67,4 +67,8 @@ const Helper = {
 const Latex = {
     /** @type {function(string, number, string): string} */
     render: (latex_markup, font_size, color) => '',
-}
+    /** @type {function(string, number, string): string} */
+    findPrerendered: (latex_markup, font_size, color) => '',
+    /** @type {function(): boolean} */
+    checkLatexInstallation: () => true,
+}

setup.py

@@ -123,7 +123,7 @@ if sys.platform == 'linux':
 
 setuptools.setup(
     install_requires=([] if "FLATPAK_INSTALL" in os.environ else ["PySide6-Essentials"]),
-    python_requires='>=3.8',
+    python_requires='>=3.9',
 
     name='logarithmplotter',
     version=pkg_version,