Add IPython.core.display.Image object output to 5 doctests

pygmt/src/coast.py

@@ -202,6 +202,7 @@ def coast(self, **kwargs):
     ... )
     >>> # Show the plot
     >>> fig.show()
+    <IPython.core.display.Image object>
     """
     kwargs = self._preprocess(**kwargs)  # pylint: disable=protected-access
     if not args_in_kwargs(args=["C", "G", "S", "I", "N", "E", "Q", "W"], kwargs=kwargs):

pygmt/src/grd2cpt.py

@@ -175,6 +175,7 @@ def grd2cpt(grid, **kwargs):
     >>> fig.grdimage(grid=grid)
     >>> # show the plot
     >>> fig.show()
+    <IPython.core.display.Image object>
     """
     if kwargs.get("W") is not None and kwargs.get("Ww") is not None:
         raise GMTInvalidInput("Set only categorical or cyclic to True, not both.")

pygmt/src/grdcontour.py

@@ -122,6 +122,7 @@ def grdcontour(self, grid, **kwargs):
     ... )
     >>> # show the plot
     >>> fig.show()
+    <IPython.core.display.Image object>
     """
     kwargs = self._preprocess(**kwargs)  # pylint: disable=protected-access
     with Session() as lib:

pygmt/src/grdimage.py

@@ -173,6 +173,7 @@ def grdimage(self, grid, **kwargs):
     >>> fig.grdimage(grid=grid, cmap="geo", projection="W10c", frame="ag")
     >>> # show the plot
     >>> fig.show()
+    <IPython.core.display.Image object>
     """
     kwargs = self._preprocess(**kwargs)  # pylint: disable=protected-access
     with Session() as lib:

pygmt/src/solar.py

@@ -89,6 +89,7 @@ def solar(self, terminator="d", terminator_datetime=None, **kwargs):
     ... )
     >>> # show the plot
     >>> fig.show()
+    <IPython.core.display.Image object>
     """
 
     kwargs = self._preprocess(**kwargs)  # pylint: disable=protected-access