Remove leading whitespace character

The manifest has two cases of leading whitespace, doesn't obviously mean
anything, remove them.

Whitespace was introduced in commit: `7d3a149ca5064147229db147359638cbcb54acdd`

Author: tcharding

Cargo.toml

@@ -22,8 +22,8 @@ unstable = ["recovery", "rand-std"]
 default = ["std"]
 std = ["alloc", "secp256k1-sys/std"]
 # allow use of Secp256k1::new and related API that requires an allocator
- alloc = ["secp256k1-sys/alloc"]
- bitcoin-hashes-std = ["bitcoin_hashes/std"]
+alloc = ["secp256k1-sys/alloc"]
+bitcoin-hashes-std = ["bitcoin_hashes/std"]
 rand-std = ["rand/std", "rand/std_rng"]
 recovery = ["secp256k1-sys/recovery"]
 lowmemory = ["secp256k1-sys/lowmemory"]