Properly mock h5_lock, which causes issues on RTD builds

Author: dihm

docs/source/conf.py

@@ -50,7 +50,7 @@
 autodoc_typehints = 'description'
 autosummary_generate = True
 add_module_names = False
-autodoc_mock_imports = ['labscript_utils']
+autodoc_mock_imports = ['labscript_utils.h5_lock']
 
 # Prefix each autosectionlabel with the name of the document it is in and a colon
 autosectionlabel_prefix_document = True