Touch up doc and test helpers

* Fix some README.md typos

* Update DOCKER.md with Python version info

* Fix script comments

Author: pushfoo

DOCKER.md

@@ -1,12 +1,11 @@
-# Docker for a Python 3.8 Test Shim
+# I Want To Test on Python $VERSION!
 
-**TL;DR:** Run `./test_in_docker.sh 3.8` and look for red
+**TL;DR:** Run `./test_in_docker.sh 3.9` and look for red
 
-If you already know Docker well, pass a `PYTHON_VERSION` via Docker's
-`--build-arg` option like so:
+To specify a version, you can manually configure it via Docker's `--build-arg` option like so:
 
 ```console
-$ docker build -f tests.Dockerfile --build-arg="PY_VERSION=3.8" -t fontknife:3.8 .
+$ docker build -f tests.Dockerfile --build-arg="PY_VERSION=3.9" -t fontknife:3.9 .
 ```
 
 However, the helper script is shorter.
@@ -27,8 +26,8 @@ First, makes you're capable of running Docker containers. For a *NIX system (mac
 the steps will be roughly as follows:
 
 1. `cd` into the project root directory
-2. Read `run_tests_in_docker.sh` to make sure you understand it
-3. Run `sudo ./test_python38.sh` and watch the output
+2. Read `test_in_docker.sh` to make sure you understand it
+3. Run `sudo ./test_in_docker.sh` and watch the output
 
 ## I don't like Docker!
 

README.md

@@ -25,11 +25,11 @@ If you only want to convert fonts, follow these steps:
 1. Have [Python](https://python.org) 3.9+ installed
 2. Make sure you've [created](https://docs.python.org/3/library/venv.html#creating-virtual-enviroments)
    and [activated](https://docs.python.org/3/library/venv.html#how-venvs-work)
-   a virtual environemnt (or use [pipx](https://pypa.github.io/pipx/))
-3. `pip install
+   a virtual environment (or use [pipx](https://pypa.github.io/pipx/))
+3. `pip install`
 4. Run `fontknife convert --help`
 
-If the last command print help text, you're ready to go! Read it for a descirption of supported arguments.
+If the last command prints help text, you're ready to go! Read it for more information about supported features.
 
 ### Developers / Contributors
 

tests.Dockerfile

@@ -1,6 +1,6 @@
 # Helper for running arbitary Python versions
 #
-# It's easiest to run this with the included script (test_python38.sh)
+# It's easiest to run this with the included script (test_in_docker.sh)
 # See doc/DOCKER.md for more info.
 ARG PYTHON_VERSION
 FROM python:${PYTHON_VERSION} AS base
@@ -23,4 +23,4 @@ RUN python -m pip install -e .[dev]
 
 # Set the container to run the helper script unless
 # otherwise specified by docker run -i -t $YOUR_COMMAND_HERE
-CMD [ 'bash', 'container.sh' ]
+CMD [ "bash", "container.sh" ]