Fixed a typo in ld2420 docs. (esphome#4520)

components/sensor/ld2420.rst

@@ -159,7 +159,7 @@ The dynamic UI provides three operational modes: **Normal**, **Calibrate** and *
 you to choose the active mode.
 
 - **Normal**: This is the default mode. It sets the ld2420 in energy reporting mode and is availble with firmware
-  v1.5.4 or greater. When in this mode the module logs all gate energy levels continuouly in a local array making it
+  v1.5.4 or greater. When in this mode the module logs all gate energy levels continuously in a local array making it
   available for dynamic calibration functions.
 - **Calibrate**: When calibration mode is selected the module will collect the average and peak energy levels,
   reporting them every five seconds. The report is provided in the log console for information only. In order to