docs: spelling

README.md

@@ -9,15 +9,15 @@ support for Large Language Model Templates.
 The key idea is to track "named-holes" in templates at type-checking (typing)
 time. This means:
 
-- You never need to debug an accidental subsitution for the wrong variable name.
-- You can substite for some variables but not others, in any order you like, and the remaining
+- You never need to debug an accidental substitution for the wrong variable name.
+- You can substitute for some variables but not others, in any order you like, and the remaining
   variables are tracked in the type.
-- You can subsitute templates with more holes into a named-hole in a template, and you get the
+- You can substitute templates with more holes into a named-hole in a template, and you get the
   correct remaining holes in the right places in the final template.
-- The same hole can appear in multiple places, subsitution substitutes it everywhere, as you would
+- The same hole can appear in multiple places, substitution substitutes it everywhere, as you would
   expect.
-- There is support for few-shot prompts (where you have some iterated template
-  over a data strutcure).
+- There is support for few-shot prompts (where you have some iterated sub-template over a data
+  structure).
 
 Here's a mini-example: