doc: fix typo [skip ci]
Error introduced in commit
@@ -48,7 +48,7 @@ optimization. However building both library types on all builds is
slow and wasteful.
Your project should use the `library` method that can be toggled
-between shared and static with the `defaul_library` builtin option.
+between shared and static with the `default_library` builtin option.
```meson
