Merge remote-tracking branch 'upstream/main' into update_removed_stdlib_modules

% Conflicts:
%	config.json

Author: fridewald

concepts/tail-call-optimisation/.meta/config.json

@@ -1,5 +1,5 @@
 {
-  "blurb": "A function call is a tail-call if it is the last thing executed by the. Tail-calls are optimised to avoid adding a new stack frame for the function call.",
+  "blurb": "A function call is a tail-call if it is the last thing executed by the calling function. Tail-calls are optimised to avoid adding a new stack frame for the function call.",
   "authors": [
     "lpil"
   ],