Fix a typo and touch up documentation (#15108)

This PR closes #15101. I fixed a typo and touched up some sentences.

Author: ehuss

src/doc/man/cargo-metadata.md

@@ -13,9 +13,9 @@ cargo-metadata --- Machine-readable metadata about the current package
 Output JSON to stdout containing information about the workspace members and
 resolved dependencies of the current package.
 
-The format of the output is subject to change in futures versions of Cargo. It
+The output format is subject to change in future versions of Cargo. It
 is recommended to include the `--format-version` flag to future-proof your code
-to ensure the output is in the format you are expecting. For more on the
+and ensure the output is in the format you are expecting. For more on the
 expectations, see ["Compatibility"](#compatibility).
 
 See the [cargo_metadata crate](https://crates.io/crates/cargo_metadata)

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

@@ -10,10 +10,10 @@ DESCRIPTION
        Output JSON to stdout containing information about the workspace members
        and resolved dependencies of the current package.
 
-       The format of the output is subject to change in futures versions of
-       Cargo. It is recommended to include the --format-version flag to
-       future-proof your code to ensure the output is in the format you are
-       expecting. For more on the expectations, see “Compatibility”.
+       The output format is subject to change in future versions of Cargo. It
+       is recommended to include the --format-version flag to future-proof your
+       code and ensure the output is in the format you are expecting. For more
+       on the expectations, see “Compatibility”.
 
        See the cargo_metadata crate <https://crates.io/crates/cargo_metadata>
        for a Rust API for reading the metadata.

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

@@ -13,9 +13,9 @@ cargo-metadata --- Machine-readable metadata about the current package
 Output JSON to stdout containing information about the workspace members and
 resolved dependencies of the current package.
 
-The format of the output is subject to change in futures versions of Cargo. It
+The output format is subject to change in future versions of Cargo. It
 is recommended to include the `--format-version` flag to future-proof your code
-to ensure the output is in the format you are expecting. For more on the
+and ensure the output is in the format you are expecting. For more on the
 expectations, see ["Compatibility"](#compatibility).
 
 See the [cargo_metadata crate](https://crates.io/crates/cargo_metadata)

src/etc/man/cargo-metadata.1

@@ -11,9 +11,9 @@ cargo\-metadata \[em] Machine\-readable metadata about the current package
 Output JSON to stdout containing information about the workspace members and
 resolved dependencies of the current package.
 .sp
-The format of the output is subject to change in futures versions of Cargo. It
+The output format is subject to change in future versions of Cargo. It
 is recommended to include the \fB\-\-format\-version\fR flag to future\-proof your code
-to ensure the output is in the format you are expecting. For more on the
+and ensure the output is in the format you are expecting. For more on the
 expectations, see \[lq]Compatibility\[rq]\&.
 .sp
 See the \fIcargo_metadata crate\fR <https://crates.io/crates/cargo_metadata>