issue #2243 -- prefer f-strings over %-interpolation

edited docs to prefer f-strings, then str.format(), and remove %-interpolation

additional ad-hoc documentation fixes, as opportunities seen:
- replace Built-In Function (BIF) "min" variable with "mins"
- prefer BIF str(var) over "%s" % var
- reformat some code examples to clarify multiple args passed to functions
- change some single-quote strings to double-quotes for consistency
- fix mismatched parens

misc edits:
- add .vscode/ to gitignore

docs/source/Components/Commands.md

@@ -65,7 +65,7 @@ Here is a minimalistic command with no custom parsing:
 
         def func(self):
             # echo the caller's input back to the caller
-            self.caller.msg("Echo: {}".format(self.args)
+            self.caller.msg(f"Echo: {self.args}")
 
 ```
 
@@ -548,7 +548,7 @@ class CmdTestID(Command):
             self.xval = 0
         self.xval += 1
 
-        self.caller.msg("Command memory ID: {} (xval={})".format(id(self), self.xval))
+        self.caller.msg(f"Command memory ID: {id(self)} (xval={self.xval})")
 
 ```
 
@@ -651,7 +651,7 @@ thus do so asynchronously, using callbacks.
 ```python
      # in command class func()
      def callback(ret, caller):
-        caller.msg("Returned is %s" % ret)
+        caller.msg(f"Returned is {ret}")
      deferred = self.execute_command("longrunning")
      deferred.addCallback(callback, self.caller)
 ```