docs(cargo-package): alwasy include the lockfile (#15067)

### What does this PR try to resolve?

This was overlooked in #14815.

### How should we test and review this PR?

```
cargo build
target/debug/cargo help package
# and read the manpage
```

src/doc/man/cargo-package.md

@@ -26,9 +26,9 @@ stored in the `target/package` directory. This performs the following steps:
     - The original `Cargo.toml` file is rewritten and normalized.
     - `[patch]`, `[replace]`, and `[workspace]` sections are removed from the
       manifest.
-    - `Cargo.lock` is automatically included if the package contains an
-      executable binary or example target. {{man "cargo-install" 1}} will use the
-      packaged lock file if the `--locked` flag is used.
+    - `Cargo.lock` is always included. When missing, a new lock file will be
+      generated. {{man "cargo-install" 1}} will use the packaged lock file if
+      the `--locked` flag is used.
     - A `.cargo_vcs_info.json` file is included that contains information
       about the current VCS checkout hash if available, as well as a flag if the
       worktree is dirty.

src/doc/man/generated_txt/cargo-package.txt

@@ -26,9 +26,9 @@ DESCRIPTION
           o  [patch], [replace], and [workspace] sections are removed from the
              manifest.
 
-          o  Cargo.lock is automatically included if the package contains an
-             executable binary or example target. cargo-install(1) will use the
-             packaged lock file if the --locked flag is used.
+          o  Cargo.lock is always included. When missing, a new lock file will
+             be generated. cargo-install(1) will use the packaged lock file if
+             the --locked flag is used.
 
           o  A .cargo_vcs_info.json file is included that contains information
              about the current VCS checkout hash if available, as well as a

src/doc/src/commands/cargo-package.md

@@ -21,9 +21,9 @@ stored in the `target/package` directory. This performs the following steps:
     - The original `Cargo.toml` file is rewritten and normalized.
     - `[patch]`, `[replace]`, and `[workspace]` sections are removed from the
       manifest.
-    - `Cargo.lock` is automatically included if the package contains an
-      executable binary or example target. [cargo-install(1)](cargo-install.html) will use the
-      packaged lock file if the `--locked` flag is used.
+    - `Cargo.lock` is always included. When missing, a new lock file will be
+      generated. [cargo-install(1)](cargo-install.html) will use the packaged lock file if
+      the `--locked` flag is used.
     - A `.cargo_vcs_info.json` file is included that contains information
       about the current VCS checkout hash if available, as well as a flag if the
       worktree is dirty.

src/etc/man/cargo-package.1

@@ -35,9 +35,9 @@ manifest.
 .RE
 .sp
 .RS 4
-\h'-04'\(bu\h'+02'\fBCargo.lock\fR is automatically included if the package contains an
-executable binary or example target. \fBcargo\-install\fR(1) will use the
-packaged lock file if the \fB\-\-locked\fR flag is used.
+\h'-04'\(bu\h'+02'\fBCargo.lock\fR is always included. When missing, a new lock file will be
+generated. \fBcargo\-install\fR(1) will use the packaged lock file if
+the \fB\-\-locked\fR flag is used.
 .RE
 .sp
 .RS 4