docs: Fix typo in pkgconfig description
@@ -49,7 +49,7 @@ keyword arguments.
generated file. The strings must be in the form `name=value` and may
reference other pkgconfig variables,
e.g. `datadir=${prefix}/share`. The names `prefix`, `libdir` and
- `installdir` are reserved and may not be used.
+ `includedir` are reserved and may not be used.
- `version` a string describing the version of this library, used to set the
`Version:` field. (*since 0.46.0*) Defaults to the project version if unspecified.
- `d_module_versions` a list of module version flags used when compiling
