'exprn' and 'expr' naming inconsistency in derive.v

[yosakaon]

analysis/theories/derive.v

Line 1406 in 7528cc1

Lemma exprn_derivable {R : numFieldType} n (x : R) v :

analysis/theories/derive.v

Line 1415 in 7528cc1

Lemma exp_derive {R : numFieldType} n x v :

analysis/theories/derive.v

Line 1422 in 7528cc1

Lemma exp_derive1 {R : numFieldType} n x :

These three lines refer to derivation using GRing.exp but naming is inconsistent between them.