Merge pull request #10493 from tannewt/env_restart_reload

Add restart/reload note about env variables

Author: dhalbert

docs/environment.rst

@@ -53,8 +53,10 @@ Details of the toml language subset
 CircuitPython behavior
 ----------------------
 
-CircuitPython will also read the environment to configure its behavior. Other
-keys are ignored by CircuitPython. Here are the keys it uses:
+CircuitPython will also read the environment to configure its behavior. Some keys are read at
+startup once and others are read on reload (ctrl-D in the REPL). If a reload doesn't change things,
+then try a reset (a power cycle or pressing the reset button). Other keys are ignored by CircuitPython.
+Here are the keys it uses:
 
 Core CircuitPython keys
 ^^^^^^^^^^^^^^^^^^^^^^^