Issue #1399334 by ArtistConk: Two small grammar fixes.

core/INSTALL.mysql.txt

@@ -18,7 +18,7 @@ initial database files. Next you must log in and set the access database rights:
   mysql -u username -p
 
 Again, you will be asked for the 'username' database password. At the MySQL
-prompt, enter following command:
+prompt, enter the following command:
 
   GRANT SELECT, INSERT, UPDATE, DELETE, CREATE, DROP, INDEX, ALTER
   ON databasename.*

core/MAINTAINERS.txt

@@ -6,7 +6,7 @@ Branch maintainers
 ------------------
 
 The Drupal Core branch maintainers oversee the development of Drupal as a
-whole. The branch mainainers for Drupal 8 are:
+whole. The branch maintainers for Drupal 8 are:
 
 - Dries Buytaert 'dries' <http://drupal.org/user/1>
 - Nathaniel Catchpole 'catch' <http://drupal.org/user/35733>