doxygen: fix filter patterns
@@ -1003,7 +1003,7 @@ INPUT_FILTER =
# need to set EXTENSION_MAPPING for the extension otherwise the files are not
# properly processed by doxygen.
-FILTER_PATTERNS = "*.md=@MARKDOWN_LINK_CONVERTER@"
+FILTER_PATTERNS = *.md="@MARKDOWN_LINK_CONVERTER@"
# If the FILTER_SOURCE_FILES tag is set to YES, the input filter (if set using
# INPUT_FILTER) will also be used to filter the input files that are used for
