zcash_primitives: Revert to SproutProof::PHGR

Unlike regular acronyms or abbreviations, this is author initials, which
we've decided to keep capitalised.

zcash_primitives/CHANGELOG.md

@@ -17,10 +17,8 @@ and this library adheres to Rust's notion of
   - `zcash_primitives::prover`
   - `zcash_primitives::redjubjub`
   - `zcash_primitives::util::{hash_to_scalar, generate_random_rseed}`
-- Renamed the following in `zcash_primitives::transaction::components` to use
-  lower-case abbreviations (matching Rust naming conventions):
-  - `JSDescription` to `JsDescription`
-  - `SproutProof::PHGR` to `SproutProof::Phgr`
+- Renamed `zcash_primitives::transaction::components::JSDescription` to
+  `JsDescription` (matching Rust naming conventions).
 
 ## [0.5.0] - 2021-03-26
 ### Added

zcash_primitives/src/transaction/components/sprout.rs

@@ -13,14 +13,15 @@ const ZC_NUM_JS_OUTPUTS: usize = 2;
 #[derive(Clone)]
 pub(crate) enum SproutProof {
     Groth([u8; GROTH_PROOF_SIZE]),
-    Phgr([u8; PHGR_PROOF_SIZE]),
+    #[allow(clippy::upper_case_acronyms)]
+    PHGR([u8; PHGR_PROOF_SIZE]),
 }
 
 impl std::fmt::Debug for SproutProof {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> Result<(), std::fmt::Error> {
         match self {
             SproutProof::Groth(_) => write!(f, "SproutProof::Groth"),
-            SproutProof::Phgr(_) => write!(f, "SproutProof::PHGR"),
+            SproutProof::PHGR(_) => write!(f, "SproutProof::PHGR"),
         }
     }
 }
@@ -121,7 +122,7 @@ impl JsDescription {
             // - Proof validity is enforced by JSDescription::Verify() in zcashd
             let mut proof = [0u8; PHGR_PROOF_SIZE];
             reader.read_exact(&mut proof)?;
-            SproutProof::Phgr(proof)
+            SproutProof::PHGR(proof)
         };
 
         let mut ciphertexts = [[0u8; 601]; ZC_NUM_JS_OUTPUTS];
@@ -158,7 +159,7 @@ impl JsDescription {
 
         match &self.proof {
             SproutProof::Groth(p) => writer.write_all(p)?,
-            SproutProof::Phgr(p) => writer.write_all(p)?,
+            SproutProof::PHGR(p) => writer.write_all(p)?,
         }
 
         writer.write_all(&self.ciphertexts[0])?;