fix(grfn/emacs): Give all snippets a unique uuid

Change-Id: Iae2ce3783bc2632b265641e286b4145373c7a226
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8478
Reviewed-by: grfn <grfn@gws.fyi>
Autosubmit: grfn <grfn@gws.fyi>
Tested-by: BuildkiteCI

users/grfn/emacs.d/snippets/rust-mode/async test

@@ -1,6 +1,6 @@
 # -*- mode: snippet -*-
 # name: async test
-# uuid:
+# uuid: atest
 # key: atest
 # condition: t
 # --

users/grfn/emacs.d/snippets/rust-mode/benchmark

@@ -1,6 +1,6 @@
 # -*- mode: snippet -*-
 # name: benchmark
-# uuid:
+# uuid: benchmark
 # key: bench
 # condition: t
 # --

users/grfn/emacs.d/snippets/rust-mode/proptest

@@ -1,6 +1,6 @@
 # -*- mode: snippet -*-
 # name: proptest
-# uuid:
+# uuid: proptest
 # key: proptest
 # condition: t
 # --

users/grfn/emacs.d/snippets/rust-mode/test-module

@@ -1,6 +1,6 @@
 # -*- mode: snippet -*-
 # name: test-module
-# uuid:
+# uuid: test-module
 # key: tmod
 # condition: t
 # --