Add TODOs

docs/Dev_ToDo.md

@@ -74,7 +74,7 @@
 - Change formation energy plotting and tabulation to `DefectPhaseDiagram` methods rather than standalone
   functions – with `pymatgen` update what's the new architecture?
 - Better automatic defect formation energy plot colour handling (auto-change colormap based on number of defects, set similar colours for similar defects (types and inequivalent sites)) – and more customisable?
-  - `aide` labelling of defect species in formation energy plots?
+  - `aide` labelling of defect species in formation energy plots? See `labellines` package for this (as used in `pymatgen-analysis-defects` chempots plotting)
   - Ordering of defects plotted (and thus in the legend) should be physically relevant (whether by energy, or defect type etc.)
   - Should have `ncols` as an optional parameter for the function, and auto-set this to 2 if the legend height exceeds that of the plot
   - Don't show transition levels outside of the bandgap (or within a certain range of the band edge, possibly using `pydefect` delocalisation analysis?), as these are shallow and not calculable with the standard supercell approach.

doped/chemical_potentials.py

@@ -1117,6 +1117,8 @@ def __init__(self, system, extrinsic_species=None):
         if extrinsic_species:
             self.elemental.append(extrinsic_species)
 
+    # TODO: Need to be able to deal with cases where the bulk composition is found to be
+    #  unstable (in `pymatgen-analysis-defects` it just drops it to the convex hull)
     # TODO: from_vaspruns and from_csv should be @classmethods so CompetingPhaseAnalyzer can be directly
     #  initialised from them (like Structure.from_file or Distortions.from_structures in SnB etc)
     def from_vaspruns(self, path="competing_phases", folder="vasp_std", csv_path=None):