maint: remove mentions of yt/extern in doc and config files

.coveragerc

@@ -9,7 +9,6 @@ omit=*.yml
 	 */__config__.py
 	 */tests/*
 	 yt/analysis_modules/*
-	 yt/extern/*
 	 yt/mods.py
 	 yt/utilities/fits_image.py
 	 yt/utilities/lodgeit.py

.github/PULL_REQUEST_TEMPLATE.md

@@ -23,7 +23,7 @@ detail.  Why is this change required?  What problem does it solve?-->
 - [ ] pass `black --check yt/`
 - [ ] pass `isort . --check --diff`
 - [ ] pass `flake8 yt/`
-- [ ] pass `flynt yt/ --fail-on-change --dry-run -e yt/extern`
+- [ ] pass `flynt yt/ --fail-on-change --dry-run`
 - [ ] New features are documented, with docstrings and narrative docs
 - [ ] Adds a test for any bugs fixed. Adds tests for new features.
 

CONTRIBUTING.rst

@@ -410,10 +410,6 @@ the following subdirectories:
    All broadly useful code that doesn't clearly fit in one of the other
    categories goes here.
 
-``extern``
-   Bundled external modules (i.e. code that was not written by one of
-   the yt authors but that yt depends on) lives here.
-
 
 If you're looking for a specific file or function in the yt source code, use
 the unix find command:
@@ -740,7 +736,7 @@ Then run the checks from the top level of the repository with
     $ flake8 yt/
     $ black --check yt/
     $ isort --check yt/
-    $ flynt --fail-on-change --dry-run -e yt/extern yt/
+    $ flynt --fail-on-change --dry-run yt/
 
 These will respectively print out any ``flake8`` errors or warnings that your newly added
 code triggers, and a list of files that are currenlty not compliant with ``black``. Note

CREDITS

@@ -127,9 +127,7 @@ Contributors:
                 Michael Zingale (michael.zingale@stonybrook.edu)
                 John ZuHone (jzuhone@gmail.com)
 
-Several items included in the yt/extern directory were written by other
-individuals and may bear their own license, including the progressbar module by
-Nilton Volpato.  The PasteBin interface code (as well as the PasteBin itself)
+The PasteBin interface code (as well as the PasteBin itself)
 was written by the Pocoo collective (pocoo.org).  
 developed by Oliver Hahn.  
 

doc/Makefile

@@ -49,7 +49,7 @@ html:
 ifneq ($(READTHEDOCS),True)
 	SPHINX_APIDOC_OPTIONS=members,undoc-members,inherited-members,show-inheritance sphinx-apidoc \
         -o source/reference/api/ \
-        -e ../yt ../yt/extern* $(shell find ../yt -name "*tests*" -type d) ../yt/utilities/voropp* ../yt/analysis_modules/*
+        -e ../yt $(shell find ../yt -name "*tests*" -type d) ../yt/utilities/voropp* ../yt/analysis_modules/*
 endif
 	$(SPHINXBUILD) -b html $(ALLSPHINXOPTS) $(BUILDDIR)/html
 	@echo

pyproject.toml

@@ -27,7 +27,6 @@ exclude = '''
   | buck-out
   | build
   | dist
-  | yt/extern
   | yt/frontends/stream/sample_data
 )/
 | yt/visualization/_colormap_data.py
@@ -39,7 +38,7 @@ exclude = '''
 profile = "black"
 combine_as_imports = true
 # isort can't be applied to yt/__init__.py because it creates circular imports
-skip =  ["venv", "benchmarks", "yt/__init__.py", "yt/extern"]
+skip =  ["venv", "benchmarks", "yt/__init__.py"]
 known_third_party = [
   "IPython",
   "nose",

setup.cfg

@@ -9,15 +9,13 @@
 #      api.py, mods.py, _mpl_imports.py, and __init__.py files to avoid spurious 
 #      unused import errors
 #      autogenerated __config__.py files
-#      vendored libraries
 max-line-length=88
 exclude = doc,
           benchmarks,
           */api.py,                          # avoid spurious "unused import"
           yt/convenience.py,                 # avoid spurious "unused import"
           */__init__.py,                     # avoid spurious "unused import"
           */__config__.py,                   # autogenerated
-          yt/extern,                         # vendored libraries
           yt/units,                          # wrapper around unyt, avoid spurious "unused import"
           yt/frontends/stream/sample_data,   # autogenerated