blas,lapack: clean up docs and comments

Apply (with manual curation after the fact):
* s/^T/U+1d40/g
* s/^H/U+1d34/g
* s/, {2,3}if / $1/g

Some additional manual editing of odd formatting.

lapack/testlapack/dpbtrs.go

@@ -74,7 +74,7 @@ func dpbtrsTest(t *testing.T, impl Dpbtrser, rnd *rand.Rand, uplo blas.Uplo, n,
 		}
 	}
 
-	// Solve  U^T * U * X = B  or  L * L^T * X = B.
+	// Solve  Uᵀ * U * X = B  or  L * Lᵀ * X = B.
 	impl.Dpbtrs(uplo, n, kd, nrhs, abFac, ldab, b, ldb)
 	xGot := b