added an undefined section to glossary

src/content/docs/appendices/glossary.mdx

@@ -21,7 +21,7 @@ description: Terminology and names related to GraphRAG
 
 - GraphRAG -- RAG using a knowledge graph
 
-### H - Z
+### H - U
 
 - Labeled Property Graph (LPG) -- an alternative name for the Property Graph Model
 
@@ -37,9 +37,17 @@ description: Terminology and names related to GraphRAG
 
 - Relationship - a data record containing an ordered pair of nodes in the Property Graph Model
 
+### V - Z
+
 - Vector -- a matrix with one row or column
 
 - Vector Embedding -- a vector representation of other data. Can be derived from words, images or even graph structures
 
 - Vertex -- 
-  1. in geometry, the meeting point of two lines that form an angle
+  1. in geometry, the meeting point of two lines that form an angle
+
+### Unsorted and undefined
+
+- Query-focused summarization (QFS)
+  - See [LMGQS: A Large-scale Dataset for Query-focused Summarization](https://arxiv.org/abs/2305.13086)
+