Fix PEP8 issues

Author: snbianco

astroquery/mast/observations.py

@@ -434,17 +434,16 @@ def _filter_ffi_observations(self, observations):
                         "If you need a TESS image for an entire field, please see our "
                         "dedicated page for downloading larger quantities of TESS data at \n"
                         "https://archive.stsci.edu/tess/. Data products will not be fetched "
-                        "for the following observations IDs: \n"
-                        + "\n".join(tess_ffis))
+                        "for the following observations IDs: \n" + "\n".join(tess_ffis))
 
         if tica_ffis.size:
             # Warn user if TICA FFIs exist
             log.warning("Because of their large size, Astroquery should not be used to "
                         "download TICA FFI products.\n"
                         "Please see our dedicated page for downloading larger quantities of "
                         "TICA data: https://archive.stsci.edu/hlsp/tica.\n"
-                        "Data products will not be fetched for the following observation IDs: \n"
-                        + "\n".join(tica_ffis))
+                        "Data products will not be fetched for the following "
+                        "observation IDs: \n" + "\n".join(tica_ffis))
 
         # Filter out FFIs with a mask
         mask = (obs_table['target_name'] != 'TESS FFI') & (obs_table['target_name'] != 'TICA FFI')