Fix missing separator error in docs Makefile (#683)

CHANGELOG.md

@@ -92,6 +92,8 @@ gets uploaded to AzureML, by skipping all test folders.
 - ([#632](https://github.com/microsoft/InnerEye-DeepLearning/pull/632)) Nifti test data is no longer stored in Git LFS
 
 ### Fixed
+
+- ([#683](https://github.com/microsoft/InnerEye-DeepLearning/pull/683)) Fix missing separator error in docs Makefile.
 - ([#659](https://github.com/microsoft/InnerEye-DeepLearning/pull/659)) Fix caching and checkpointing for TCGA CRCk dataset.
 - ([#649](https://github.com/microsoft/InnerEye-DeepLearning/pull/649)) Fix for the _convert_to_tensor_if_necessary method so that PIL.Image as well as np.array get converted to torch.Tensor.
 - ([#606](https://github.com/microsoft/InnerEye-DeepLearning/pull/606)) Bug fix: registered models do not include the hi-ml submodule

sphinx-docs/Makefile

@@ -17,7 +17,7 @@ help:
 # Do some preprocessing, including copying over md files to the source directory so sphinx can find them,
 # and changing references to codefiles in md files to urls.
 preprocess:
-    python preprocess.py
+	python preprocess.py
 
 # Catch-all target: route all unknown targets to Sphinx using the new
 # "make mode" option.  $(O) is meant as a shortcut for $(SPHINXOPTS).