Improve docs.

Signed-off-by: Rolf Schröder <rolf.schr@gmail.com>

Author: rolfschr

README.rst

@@ -146,7 +146,7 @@ There are several options to use the Nix version
 
 ::
 
-    # Enter an interactive environment with all dependencies setup.
+    # Enter an interactive environment with all dependencies set up.
     cd etc/nix
     nix develop
     > ../../manage.py ... # invoke the local checkout
@@ -162,7 +162,7 @@ There are several options to use the Nix version
 
 The Nix installation uses `mach-nix <https://github.com/DavHau/mach-nix>`__ to handle Python dependencies because some dependencies are currently not available as Nix packages.
 All Python dependencies are automatically fetched from ``./requirements.txt``.
-Non-Python dependencies are curated in ``etc/nix/flake.nix:Vulnerablecode.propagatedBuildInputs``.
+Non-Python dependencies are curated in ``etc/nix/flake.nix:vulnerablecode.propagatedBuildInputs``.
 
 
 Tests

etc/nix/flake.nix

@@ -25,6 +25,7 @@
       version = builtins.head (builtins.match ''.*version=["']?([^"',]+).*''
         (builtins.readFile (vulnerablecode-src + "/setup.py")));
 
+      # Common shell code.
       libSh = ./lib.sh;
 
       # System types to support.

etc/nix/lib.sh

@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 
-# Setup postgres; see the README.md for the the latest instructions.
+# Setup postgres; see the README.md for the latest instructions.
 #
 # $RUNDIR is used to prevent postgres from accessings its default run dir at
 # /run/postgresql. See