Document openvino-finder further in README

Author: abrown

crates/openvino-finder/README.md

@@ -1,7 +1,15 @@
 openvino-finder
 ===============
 
-A utility for locating OpenVINO™ libraries on a host system.
+A utility for locating OpenVINO™ libraries on a host system. It will attempt to find the OpenVINO
+shared libraries in:
+- the `OPENVINO_INSTALL_DIR` environment variable (pointed at the top-level OpenVINO installation,
+  e.g. `/opt/intel/openvino`)
+- the `INTEL_OPENVINO_DIR` environment variable (same as above; this is set by OpenVINO setup
+  scripts)
+- the environment's library path (e.g., `LD_LIBRARY_PATH` in Linux; this is also set by the OpenVINO
+  setup scripts)
+- OpenVINO's default installation paths for the OS (a best effort attempt)
 
 > #### WARNING
 > This crate is currently experimental--its API surface is subject to change.