Fix some typos

Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
diff --git a/ChangeLog.d/cipher-delayed-output.txt b/ChangeLog.d/cipher-delayed-output.txt
index 0c8f7db..4ca3a0c 100644
--- a/ChangeLog.d/cipher-delayed-output.txt
+++ b/ChangeLog.d/cipher-delayed-output.txt
@@ -1,6 +1,6 @@
 API changes
-   * For multi-part AEAD operations with the Cipher module, calling
+   * For multi-part AEAD operations with the cipher module, calling
      mbedtls_cipher_finish() is now mandatory. Previously the documentation
      was unclear on this point, and this function happened to never do
-     anything with the currently implemented AEADs, so in practice is was
+     anything with the currently implemented AEADs, so in practice it was
      possible to skip calling it, which is no longer supported.
diff --git a/docs/3.0-migration-guide.d/cipher-delayed-output.md b/docs/3.0-migration-guide.d/cipher-delayed-output.md
index e376880..18d3271 100644
--- a/docs/3.0-migration-guide.d/cipher-delayed-output.md
+++ b/docs/3.0-migration-guide.d/cipher-delayed-output.md
@@ -1,7 +1,7 @@
 Calling `mbedtls_cipher_finish()` is mandatory for all multi-part operations
 ----------------------------------------------------------------------------
 
-This only affect people who use the Cipher module to perform AEAD operations
+This only affects people who use the cipher module to perform AEAD operations
 using the multi-part API.
 
 Previously, the documentation didn't state explicitly if it was OK to call