SCons: Format buildsystem files with psf/black

Configured for a max line length of 120 characters.

psf/black is very opinionated and purposely doesn't leave much room for
configuration. The output is mostly OK so that should be fine for us,
but some things worth noting:

- Manually wrapped strings will be reflowed, so by using a line length
  of 120 for the sake of preserving readability for our long command
  calls, it also means that some manually wrapped strings are back on
  the same line and should be manually merged again.

- Code generators using string concatenation extensively look awful,
  since black puts each operand on a single line. We need to refactor
  these generators to use more pythonic string formatting, for which
  many options are available (`%`, `format` or f-strings).

- CI checks and a pre-commit hook will be added to ensure that future
  buildsystem changes are well-formatted.

2 files changed, 7 insertions, 4 deletions

diff --git a/modules/upnp/SCsub b/modules/upnp/SCsub
index 3f56a69594..2e129e15ca 100644
--- a/modules/upnp/SCsub
+++ b/modules/upnp/SCsub
@@ -1,13 +1,13 @@
 #!/usr/bin/env python
 
-Import('env')
-Import('env_modules')
+Import("env")
+Import("env_modules")
 
 env_upnp = env_modules.Clone()
 
 # Thirdparty source files
 
-if env['builtin_miniupnpc']:
+if env["builtin_miniupnpc"]:
     thirdparty_dir = "#thirdparty/miniupnpc/"
     thirdparty_sources = [
         "miniupnpc.c",
diff --git a/modules/upnp/config.py b/modules/upnp/config.py
index 8724ff1a51..3e15b940a1 100644
--- a/modules/upnp/config.py
+++ b/modules/upnp/config.py
@@ -1,14 +1,17 @@
 def can_build(env, platform):
     return True
 
+
 def configure(env):
     pass
 
+
 def get_doc_classes():
     return [
         "UPNP",
-        "UPNPDevice"
+        "UPNPDevice",
     ]
 
+
 def get_doc_path():
     return "doc_classes"