Clarify FPDF.add_font()'s style parameter accepted values (#1263)

CHANGELOG.md

@@ -54,6 +54,7 @@ This can also be enabled programmatically with `warnings.simplefilter('default',
 * [`FPDF.write_html()`](https://py-pdf.github.io/fpdf2/fpdf/fpdf.html#fpdf.fpdf.FPDF.write_html): indentation of HTML elements can now be non-integer (float), and is now independent of font size and bullet strings.
 * improved performance of font glyph selection by using functools cache
 - New translation of the tutorial in Türkçe, thanks to @natgho: [Türkçe](https://py-pdf.github.io/fpdf2/Tutorial-tr.html); 
+* Clarified usage of the `style` attribute in [`FPDF.add_font()`](https://py-pdf.github.io/fpdf2/fpdf/fpdf.html#fpdf.fpdf.FPDF.add_font)
 
 ## [2.7.9] - 2024-05-17
 ### Added

fpdf/fpdf.py

@@ -1888,7 +1888,7 @@ def add_font(self, family=None, style="", fname=None, uni="DEPRECATED"):
         Args:
             family (str): optional name of the font family. Used as a reference for `FPDF.set_font()`.
                 If not provided, use the base name of the `fname` font path, without extension.
-            style (str): font style. "B" for bold, "I" for italic.
+            style (str): font style. "" for regular, include 'B' for bold, and/or 'I' for italic.
             fname (str): font file name. You can specify a relative or full path.
                 If the file is not found, it will be searched in `FPDF_FONT_DIR`.
             uni (bool): [**DEPRECATED since 2.5.1**] unused