DOC: use backend spelling everywhere

Author: dnicolodi

README.rst

@@ -5,7 +5,7 @@
 meson-python
 ============
 
-``meson-python`` is a Python build backend built on top of the Meson__
+``meson-python`` is a Python build back-end built on top of the Meson__
 build system. It enables using Meson for the configuration and build
 steps of Python packages. Meson is an open source build system meant
 to be both extremely fast, and, even more importantly, as user

docs/index.rst

@@ -10,7 +10,7 @@ meson-python
 
 .. highlights::
 
-  A Python package build back-end leveraging the Meson build system.
+  A Python package build backend leveraging the Meson build system.
 
 ``meson-python`` implement the Python build system hooks, enabling Python build
 front-ends such as ``pip`` and ``build`` to build and install Python packages
@@ -35,7 +35,7 @@ To enable ``pip`` or ``build`` to build a Python source distribution (*sdist*)
 or a binary Python package (*wheel*) for a Meson project, it is sufficient to
 add to the root of the source tree next to the top-level ``meson.build`` a
 ``pyproject.toml`` file specifying ``meson-python`` as the Python build
-back-end:
+backend:
 
 .. code-block:: toml