doc: Remove two redundant characters in rst file

Remove additional dot and bracket.

Signed-off-by: Marcin Gasiorek <marcin.gasiorek@nordicsemi.no>
diff --git a/doc/kernel/memory_management/slabs.rst b/doc/kernel/memory_management/slabs.rst
index 72d2763..ae57a78 100644
--- a/doc/kernel/memory_management/slabs.rst
+++ b/doc/kernel/memory_management/slabs.rst
@@ -71,7 +71,7 @@
 It must then be initialized by calling :c:func:`k_mem_slab_init`.
 
 The following code defines and initializes a memory slab that has 6 blocks
-that are 400 bytes long, each of which is aligned to a 4-byte boundary..
+that are 400 bytes long, each of which is aligned to a 4-byte boundary.
 
 .. code-block:: c
 
@@ -109,7 +109,7 @@
 
     char *block_ptr;
 
-    if (k_mem_slab_alloc(&my_slab, &block_ptr, 100) == 0)) {
+    if (k_mem_slab_alloc(&my_slab, &block_ptr, 100) == 0) {
         memset(block_ptr, 0, 400);
 	...
     } else {