Apply suggestions from code review

Co-authored-by: Daniel McCloy <[email protected]>

Author: drammock

doc/changes/dev/13778.newfeature.rst

@@ -1 +1 @@
-Added a ``font_file`` parameter to :meth:`mne.viz.Brain.add_text` to allow custom ``.ttf``/``.ttc`` fonts for improved Unicode glyph rendering, by `Pragnya Khandelwal`_.
+Added a ``font_file`` parameter to :meth:`mne.viz.Brain.add_text` to support rendering glyphs not available in the default font, by `Pragnya Khandelwal`_.

mne/viz/_brain/_brain.py

@@ -2827,9 +2827,8 @@ def add_text(
             The text justification.
         font_file : str | None
             Path to an absolute path of a font file to use for rendering
-            the text. FreeType is used for loading, supporting many font
-            formats beyond ``.ttf`` and ``.ttc``. This can be helpful for
-            non-ASCII glyph coverage.
+            the text. See https://freetype.org/freetype2/docs/index.html for a list of
+            supported font file formats.
         """
         _validate_type(name, (str, None), "name")
         name = text if name is None else name