refactor: Slight adjustments to doc-strings

HepLean/Tensors/Tree/Elab.lean

@@ -39,8 +39,8 @@ import HepLean.Lorentz.ComplexTensor.Basic
 ## Comments
 
 - In all of theses expressions `μ`, `ν` etc are free. It does not matter what they are called,
-  Lean will elaborate them in the same way. I.e. `{T | μ ν ⊗ T3 | μ ν }ᵀ` is exactly the same
-  to Lean as `{T | α β ⊗ T3 | α β }ᵀ`.
+  Lean will elaborate them in the same way. In other words, `{T | μ ν ⊗ T3 | μ ν }ᵀ` is exactly
+  the same to Lean as `{T | α β ⊗ T3 | α β }ᵀ`.
 - Note that compared to ordinary index notation, we do not rise or lower the indices.
   This is for two reasons: 1) It is difficult to make this general for all tensor species,
   2) It is a redundancy in ordinary index notation, since the tensor `T` itself already tells you