Update grc to latest version upstream

Specifically update to commit f7959cbcb09e989381171198c266939e0d715488
which updates the comments in grc.config to include the commit id
for the Perseus Corpus used to generate the wordlist.

grc/grc.config

@@ -1,6 +1,9 @@
 # Tesseract Ancient Greek training <http://ancientgreekocr.org>
 # Build from the http://ancientgreekocr.org/grctraining.git repository
-# commit: 9441cf218415bec9d46bd61243747ba10bee057e
+# commit: f7959cbcb09e989381171198c266939e0d715488
+#
+# Wordlists derived from https://github.com/PerseusDL/canonical-greekLit
+# commit: 5d069b29bd9dd40c8bb1dc1b9e2623236ebb22b9
 
 # New segsearch produces better results
 enable_new_segsearch 1