Update doc

Author: glemaitre

doc/developers_utils.rst

@@ -1,10 +1,10 @@
 .. _developers-utils:
 
 ========================
-Utilities for Developers
+Utilities for developers
 ========================
 
-Imbalanced-learn contains a number of utilities to help with development.  These are
+Imbalanced-learn contains a number of utilities to help with development. These are
 located in :mod:`imblearn.utils`, and include tools in a number of categories.
 All the following functions and classes are in the module :mod:`imblearn.utils`.
 
@@ -20,7 +20,7 @@ All the following functions and classes are in the module :mod:`imblearn.utils`.
 Validation Tools
 ================
 
-These are tools used to check and validate input.  When you write a function
+These are tools used to check and validate input. When you write a function
 which accepts arrays, matrices, or sparse matrices as arguments, the following
 should be used when applicable.