Clarify docs about import directory with path.
Trailing slash is required only with relative paths. Fixes
@@ -108,7 +108,8 @@ If the library is a file, the path to it must contain extension. For
Python libraries the extension is naturally :file:`.py` and for Java
libraries it can either be :file:`.class` or :file:`.java`, but the
class file must always be available. If Python library is implemented
-as a directory, the path to it must have a trailing forward slash (`/`).
+as a directory, the path to it must have a trailing forward slash (`/`)
+if the path is relative. With absolute paths the trailing slash is optional.
Following examples demonstrate these different usages.
.. sourcecode:: robotframework
