Typos in comments

compiler/llvmGen/LlvmCodeGen/CodeGen.hs

@@ -1667,7 +1667,7 @@ genLit _ CmmHighStackMark
 -- and avoids having to deal with Phi node insertion.  This is also
 -- the approach recommended by LLVM developers.
 --
--- On the other hand, this is unecessarily verbose if the register in
+-- On the other hand, this is unnecessarily verbose if the register in
 -- question is never written. Therefore we skip it where we can to
 -- save a few lines in the output and hopefully speed compilation up a
 -- bit.

compiler/typecheck/TcSMonad.hs

@@ -932,7 +932,7 @@ For example, if we have
 and we wish to compute S(W/R, T a b), the correct answer is T a Bool, NOT
 T Int Bool. The reason is that T's first parameter has a nominal role, and
 thus rewriting a to Int in T a b is wrong. Indeed, this non-congruence of
-subsitution means that the proof in Note [The inert equalities] may need
+substitution means that the proof in Note [The inert equalities] may need
 to be revisited, but we don't think that the end conclusion is wrong.
 
 Note [Examples of how the inert_model helps completeness]

compiler/vectorise/Vectorise.hs

@@ -130,7 +130,7 @@ vectModule guts@(ModGuts { mg_tcs        = tycons
 --
 -- The original binding @foo@ is rewritten to call the vectorised version present in the closure.
 --
--- Vectorisation may be surpressed by annotating a binding with a 'NOVECTORISE' pragma.  If this
+-- Vectorisation may be suppressed by annotating a binding with a 'NOVECTORISE' pragma.  If this
 -- pragma is used in a group of mutually recursive bindings, either all or no binding must have
 -- the pragma.  If only some bindings are annotated, a fatal error is being raised. (In the case of
 -- scalar bindings, we only omit vectorisation if all bindings in a group are scalar.)

docs/backpack/algorithm.tex

@@ -671,7 +671,7 @@ we have to type-check the \I{ModIface} with the following adjustments:
           with a unit key that is a $\verb|hole|$,
           substitute with the recorded \I{Name} in the requirements of the shape.
           Otherwise, look up the (unique) \I{ModIface} for the \I{Module},
-          and subsitute with the corresponding \I{Name} in the \I{mi\_exports}.
+          and substitute with the corresponding \I{Name} in the \I{mi\_exports}.
 \end{enumerate}
 
 \paragraph{Signatures}  For signatures, we have a \I{Module} of the form