Add test for unwrapping none

Author: wezm

formats/unwrap-none.fathom

@@ -0,0 +1,4 @@
+def main = {
+    let ary : Array16 3 U16 = [1, 2, 3],
+    x <- unwrap U16 (array16_find _ U16 (fun el => el == (4 : U16)) ary),
+};

formats/unwrap-none.snap

@@ -0,0 +1,7 @@
+stdout = '''
+def main : Format = {
+    let ary : Array16 3 U16 = [ 1, 2, 3 ],
+    x <- unwrap U16 (array16_find (_ ary) U16 (fun el => el == (4 : U16)) ary),
+};
+'''
+stderr = ''

tests/cmd/fathom-data.md

@@ -291,3 +291,18 @@ error: mismatched types
 
 
 ```
+
+### Unwrap none
+
+Unwrapping a none value will result in an error
+
+```console
+$ fathom data --module formats/unwrap-none.fathom
+>             formats/data/opentype/aots/cmap0_font1.otf
+? failed
+error: unwrapped none
+ = option_unwrap was called on a none value.
+
+
+```
+