Prevent prettier from adding line breaks to excmds

.prettierrc

@@ -2,4 +2,13 @@ tabWidth: 4
 useTabs: false
 semi: false
 singleQuote: false
-arrowParens: avoid
+arrowParens: "avoid"
+trailingComma: "all"
+proseWrap: "never"
+
+# The python script which parses excmds requires that function signatures are on one line.
+# Hopefully, no-one will write a function signature more than 10,000 characters long.
+overrides:
+- files: "excmds.ts"
+  options:
+    printWidth: 10000