changing table to dataframe to reflect the variable name used in the function

Author: abostroem

episodes/07-photo.md

@@ -187,7 +187,7 @@ We want to be able to make this plot again, with any selection of PanSTARRs phot
 so this is a natural time to put it into a function that accepts as input
 an Astropy `Table` or Pandas `DataFrame`, as long as
 it has columns named `g_mean_psf_mag` and `i_mean_psf_mag`. To do this we will change
-our variable name from `candidate_df` to the more generic `table`.
+our variable name from `candidate_df` to the more generic `dataframe`.
 
 ```python
 def plot_cmd(dataframe):