Update installation guides for FreeBSD (#469)

* Update installation guides for FreeBSD

* Clarify pip installation guide

* Finalize the PR

* oops forgot to add a comma

* Atomicwrites now compiles just fine via pip on FreeBSD.

README.md

@@ -38,7 +38,7 @@ pipx creates an isolated environment for each program, and adds their binaries i
 - Install pipx using either your package manager, `pip3 install --user pipx`, or `pip install --user pipx`.
 - Run `pipx install "corrscope[qt5]"`
     - On Linux, to add support for native Qt themes, instead run `pipx install --system-site-packages "corrscope[qt5]"`
-    - On FreeBSD, install `py-qt5` and `py39-ruamel.yaml` via `pkg` or ports tree, and install `ffmpeg` via ports tree with `SDL` option enabled. After everything's installed, run `pipx install --system-site-packages "corrscope[qt5]"`
+    - On FreeBSD, install `py39-qt5` and `py39-ruamel.yaml` via `pkg` or ports tree, then run `pipx install --system-site-packages "corrscope[qt5]"`. To get previews working, install `ffmpeg` via ports tree with `SDL` option enabled.
     - On M1 Mac, instead run `pipx install "corrscope[qt6]"`
 - Open a terminal and run `corr (args)`.
 
@@ -49,6 +49,7 @@ pip installs packages into a per-user Python environment. This has the disadvant
 - Install Python 3.8 or above.
 - If necessary, install pip using your package manager.
 - Run `pip3 install --user "corrscope[qt5]"`
+    - On FreeBSD, install `py39-qt5` and `py39-ruamel.yaml` via `pkg` or ports tree, then run `pip install --user "corrscope[qt5]"`. To get previews working, install `ffmpeg` via ports tree with `SDL` option enabled.
     - On M1 Mac, instead run `pip3 install --user "corrscope[qt6]"`
 - Open a terminal and run `corr (args)`.