Fix typos in documentation

doc/DOCUMENTATION.org

@@ -1004,7 +1004,7 @@ variable =dotspacemacs-themes=. For instance, to specify =spacemacs-light=,
 #+END_SRC
 
 =dotspacemacs-themes= entries accept the same properties as packages listed
-in layers package lists or in =dotspacemacs-addtional-packages=. So it is
+in layers package lists or in =dotspacemacs-additional-packages=. So it is
 possible to fetch a package from a specific location. For example, you could
 fetch =zenburn= theme directly from the GitHub repository with the following
 declaration:

doc/FAQ.org

@@ -151,7 +151,7 @@ should not be loaded before =dotspacemacs/user-config=, otherwise both versions
 will be loaded and will conflict.
 
 Because of autoloading, calling to =org= functions will trigger the loading up
-of the =org= shipped with emacs wich will induce conflicts. One way to avoid
+of the =org= shipped with emacs which will induce conflicts. One way to avoid
 conflict is to wrap your =org= config code in a =with-eval-after-load= block
 like this:
 
@@ -515,7 +515,7 @@ some expressions to the search input:
   ending with =.el= which are emacs-lisp files.
 
 - By using a flag like =--python= which should be self-explaining. The list of
-  available flags colud be accessed from terminal with:
+  available flags could be accessed from terminal with:
 
   #+begin_src shell
   ag --list-file-types

doc/LAYERS.org

@@ -288,7 +288,7 @@ Before initializing that package, Spacemacs will add this folder to the load
 path for you.
 
 ** layers.el
-This file is the first file to be loaded and this is the place where addtional
+This file is the first file to be loaded and this is the place where additional
 layers can be declared.
 
 For instance is layer A depends on some functionality of layer B then in the