Clarify docs for logger, globals (#2323)

components/logger.rst

@@ -6,9 +6,10 @@ Logger Component
     :image: file-document-box.svg
 
 The logger component automatically logs all log messages through the
-serial port and through MQTT topics. By default, all logs with a
-severity higher than ``DEBUG`` will be shown. Decreasing the log level
-can help with the performance of the application and memory size.
+serial port and through MQTT topics (if there is an MQTT client in the
+configuration). By default, all logs with a severity higher than
+``DEBUG`` will be shown. Decreasing the log level can help with the
+performance of the application and memory size.
 
 .. code-block:: yaml
 
@@ -54,7 +55,9 @@ The logger component makes use of platform-specific hardware UARTs for serial lo
 By default, the logger will occupy ``UART0``. The ESP32 has three hardware UARTs, all of
 which can be used for both transmit and receive. The ESP8266 only has two hardware UARTs,
 one of which is transmit-only. The ESP8266 ``UART0`` can also be 'swapped' to TX/RX on the
-CTS/RTS pins, if you need to use GPIO1 and GPIO3 for something else.
+CTS/RTS pins, if you need to use GPIO1 and GPIO3 for something else. Note that the common
+NodeMCU boards have their USB-UART Adapters fixed to the default GPIOs used by ``UART0``,
+so if you use anything else you will not get log messages over the on-board USB.
 
 Possible Hardware UART configurations:
 

guides/automations.rst

@@ -274,7 +274,7 @@ global variables can be used to store the state of a garage door.
       - id: my_global_string
         type: std::string
         restore_value: no  # Strings cannot be saved/restored
-        initial_value: '"hello world"'
+        initial_value: '"Global value is"'
 
    # In an automation
    on_press:
@@ -287,7 +287,7 @@ global variables can be used to store the state of a garage door.
              id(my_global_int) += 10;
            }
 
-           ESP_LOGD(TAG, "Global value is: %d", id(my_global_int));
+           ESP_LOGD(TAG, "%s: %d", id(my_global_string), id(my_global_int));
 
 Configuration variables: