docs: configuration: Fix minor wording mistakes

Fixes minor issues in the configuration documentation.

Signed-off-by: Georgios Vasilakis <georgios.vasilakis@nordicsemi.no>
Change-Id: Ia6fa264d9ac7e25fda4513bc38c2c7e13f7b0829
diff --git a/docs/configuration/kconfig_system.rst b/docs/configuration/kconfig_system.rst
index 015d258..655d4c2 100644
--- a/docs/configuration/kconfig_system.rst
+++ b/docs/configuration/kconfig_system.rst
@@ -11,7 +11,7 @@
 It handles dependencies and validations automatically when you change configurations so that the
 generated configuration options are always valid.
 
-To use the Kconfig system, enable ``USE_KCONFIG_TOOL`` in commande line.
+To use the Kconfig system, enable ``USE_KCONFIG_TOOL`` in command line.
 And enable ``MENUCONFIG`` to launch configuration GUI.
 
 The Kconfig system consists of `The Kconfig tool`_ and the `The Kconfig files`_.
@@ -29,7 +29,7 @@
 - Header file
 
   Contains component options in the header file system.
-  Component options are gathered together in a seperate menu ``TF-M component configs`` in
+  Component options are gathered together in a separate menu ``TF-M component configs`` in
   `The Kconfig files`_.
 
 - The .config and .config.old files
@@ -44,7 +44,7 @@
 The first loaded options are overridden by later ones if the config files contain duplicated
 options.
 And dependencies between config options are taken care of.
-It then launchs a configuration GUI for users to change any config options if the ``MENUCONFIG`` is
+It then launches a configuration GUI for users to change any config options if the ``MENUCONFIG`` is
 enabled in build command line.
 
 Integration with TF-M build system