docs: correct reference to meson.build

Reviewed-by: Eric Engestrom <eric@engestrom.ch>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6915>
diff --git a/docs/meson.rst b/docs/meson.rst
index 2346a28..340287a 100644
--- a/docs/meson.rst
+++ b/docs/meson.rst
@@ -300,7 +300,7 @@
 
 -  Install the binaries and headers into the
    ``$mesa_src/subprojects/llvm``
--  Add a meson build.build file to that directory (more on that later)
+-  Add a meson.build file to that directory (more on that later)
 
 The wrap file must define the following: