Add missing code block
@@ -89,12 +89,16 @@ to build dependencies manually when they are not.
To make this work, the dependency must have Meson build definitions
and it must declare its own dependency like this:
+```meson
foo_dep = declare_dependency(...)
+```
Then any project that wants to use it can write out the following
declaration in their main `meson.build` file.
+```meson
foo_dep = dependency('foo', fallback : ['foo', 'foo_dep'])
+```
What this declaration means is that first Meson tries to look up the
dependency from the system (such as by using pkg-config). If it is not
