chore: Mark unpublished crates as such

This is a follow up to rust-lang#12039.
This makes it easier for tools to report less irrelevant information.

I did both `publish = false` and `version = "0.0.0"` to help draw
attention to the fact that these crates are internal (inspired by a
matklad post).

I left `cargo-test-macro` and `cargo-test-support` in for my own
personal bias of one day wanting to see those crates published...

The only one removed that had previously been published was `mdman` but
seeing as that was a `0.0.0`, I'm assuming that was a mistake or just
reserving the name.

Before:
```console
$ cargo unpublished
name published current
==== ========= =======
cargo-platform 0.1.2 0.1.3
cargo-test-macro - 0.1.0
cargo-test-support - 0.1.0
cargo-util 0.2.3 0.2.4
crates-io 0.36.0 0.36.1
mdman 0.0.0 0.1.0
resolver-tests - 0.1.0
cargo 0.70.1 0.72.0
semver-check - 0.1.0
cargo-credential 0.1.0 0.2.0
cargo-credential-1password 0.1.0 0.2.0
cargo-credential-gnome-secret 0.1.0 0.2.0
cargo-credential-macos-keychain 0.1.0 0.2.0
cargo-credential-wincred 0.1.0 0.2.0
benchsuite - 0.1.0
```

After:
```console
name published current
==== ========= =======
cargo-platform 0.1.2 0.1.3
cargo-test-macro - 0.1.0
cargo-test-support - 0.1.0
cargo-util 0.2.3 0.2.4
crates-io 0.36.0 0.36.1
cargo 0.70.1 0.72.0
cargo-credential 0.1.0 0.2.0
cargo-credential-1password 0.1.0 0.2.0
cargo-credential-gnome-secret 0.1.0 0.2.0
cargo-credential-macos-keychain 0.1.0 0.2.0
cargo-credential-wincred 0.1.0 0.2.0
```

benches/benchsuite/Cargo.toml

@@ -1,11 +1,12 @@
 [package]
 name = "benchsuite"
-version = "0.1.0"
+version = "0.0.0"
 edition = "2021"
 license = "MIT OR Apache-2.0"
 homepage = "https://github.com/rust-lang/cargo"
 repository = "https://github.com/rust-lang/cargo"
 description = "Benchmarking suite for Cargo."
+publish = false
 
 [dependencies]
 cargo = { path = "../.." }

crates/mdman/Cargo.toml

@@ -1,9 +1,10 @@
 [package]
 name = "mdman"
-version = "0.1.0"
+version = "0.0.0"
 edition = "2021"
 license = "MIT OR Apache-2.0"
 description = "Creates a man page page from markdown."
+publish = false
 
 [dependencies]
 anyhow = "1.0.31"

crates/resolver-tests/Cargo.toml

@@ -1,7 +1,8 @@
 [package]
 name = "resolver-tests"
-version = "0.1.0"
+version = "0.0.0"
 edition = "2018"
+publish = false
 
 [dependencies]
 cargo = { path = "../.." }

crates/semver-check/Cargo.toml

@@ -1,8 +1,9 @@
 [package]
 name = "semver-check"
-version = "0.1.0"
+version = "0.0.0"
 authors = ["Eric Huss"]
 edition = "2021"
+publish = false
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html