docs: specify profile usage for cargo test --release

Author: dlaehnemann

src/doc/src/reference/manifest.md

@@ -341,7 +341,7 @@ incremental = true # whether or not incremental compilation is enabled
 overflow-checks = true # use overflow checks for integer arithmetic.
                    # Passes the `-C overflow-checks=...` flag to the compiler.
 
-# The release profile, used for `cargo build --release` and `cargo test --release`.
+# The release profile, used for `cargo build --release` (and the dependencies for `cargo test --release`,  including the local lib/bin).
 [profile.release]
 opt-level = 3
 debug = false
@@ -353,7 +353,7 @@ panic = 'unwind'
 incremental = false
 overflow-checks = false
 
-# The testing profile, used for `cargo test`.
+# The testing profile, used for `cargo test` (for `cargo test --release` see the `release` and `bench` profiles).
 [profile.test]
 opt-level = 0
 debug = 2
@@ -365,7 +365,7 @@ panic = 'unwind'
 incremental = true
 overflow-checks = true
 
-# The benchmarking profile, used for `cargo bench`.
+# The benchmarking profile, used for `cargo bench` (and the test targets and unit tests for `cargo test --release`).
 [profile.bench]
 opt-level = 3
 debug = false