Fix typo in public/fpdf_sysfontinfo.h

In the FPDF_FreeDefaultSystemFontInfo() documentation, mention
FPDF_GetDefaultSystemFontInfo() instead of of FPDF_SetSystemFontInfo(),
as FPDF_SetSystemFontInfo() does not return anything to free.

Change-Id: Ia22e455e898324bbb4c6b22f69d3f122a7877f65
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/116750
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Thomas Sepez <tsepez@google.com>
Commit-Queue: Tom Sepez <tsepez@chromium.org>
diff --git a/public/fpdf_sysfontinfo.h b/public/fpdf_sysfontinfo.h
index 7dcf25d..e30220c 100644
--- a/public/fpdf_sysfontinfo.h
+++ b/public/fpdf_sysfontinfo.h
@@ -305,7 +305,7 @@
  *           None
  * Comments:
  *           This function should be called on the output from
- *           FPDF_SetSystemFontInfo() once it is no longer needed.
+ *           FPDF_GetDefaultSystemFontInfo() once it is no longer needed.
  */
 FPDF_EXPORT void FPDF_CALLCONV
 FPDF_FreeDefaultSystemFontInfo(FPDF_SYSFONTINFO* pFontInfo);