BUG: Export parse_wpc_surface_bulletin

The code to export and set __all__ was missing. The function was still
available from the * import, but it wasn't showing up properly in the
docs.

src/metpy/io/__init__.py

@@ -25,5 +25,6 @@
 __all__.extend(metar.__all__)  # pylint: disable=undefined-variable
 __all__.extend(nexrad.__all__)  # pylint: disable=undefined-variable
 __all__.extend(station_data.__all__)  # pylint: disable=undefined-variable
+__all__.extend(text.__all__)  # pylint: disable=undefined-variable
 
 set_module(globals())

src/metpy/io/text.py

@@ -12,6 +12,9 @@
 import pandas as pd
 
 from ._tools import open_as_needed
+from ..package_tools import Exporter
+
+exporter = Exporter(globals())
 
 
 def _decode_coords(coordinates):
@@ -64,6 +67,7 @@ def _regroup_lines(iterable):
         yield parts
 
 
+@exporter.export
 def parse_wpc_surface_bulletin(bulletin, year=None):
     """Parse a coded surface bulletin from NWS WPC into a Pandas DataFrame.