fix: sync generated hive-forge CLI docs with their clap source strings

Same bug as the swarmctl/hivectl fix, a third instance argus's review
didn't name but nix/checks.nix's hive-forge-docs freshness check (same
pattern as hivectl-docs/swarmctl-docs) caught in CI: the earlier
Contractions/Foreign/Auto batches edited docs/tools/forge-cli.md
directly instead of the clap #[arg(...)]/doc-comment strings in
hive-forge/src/main.rs and hive-forge/src/verbs/*.rs.

Applied the same 13 wording changes to source that the earlier commits
already made to the generated .md, matched 1:1 against
'git diff origin/main HEAD -- docs/tools/forge-cli.md' rather than
guessed. Several source doc comments feed two rendered sections each
(e.g. reaction.rs's one Add-variant doc renders under both
'issue reaction add' and 'pr reaction add', since both subcommands
share the same enum) -- one source fix, two generated-doc fixes.

Regenerated from the now-fixed source and confirmed byte-identical to
what's already committed (diff exit 0) -- source and generated output
are back in sync, same as the swarmctl/hivectl fix.

cargo clippy -p hive-forge --all-targets -- -D warnings and
scripts/check-doc-refs.sh both clean.

hive-forge/src/verbs/pr_merge.rs

@@ -53,13 +53,13 @@ impl Method {
 pub struct Args {
     /// PR number to merge.
     number: u64,
-    /// Merge strategy (default: a merge commit). Squash is not offered.
+    /// Merge strategy (default: a merge commit). Squash isn't offered.
     #[arg(long, value_enum, default_value = "merge")]
     method: Method,
     /// Keep the head branch after merging (deleted by default).
     #[arg(long = "keep-branch")]
     keep_branch: bool,
-    /// Merge even if the PR is not mergeable, CI is not green, or a review
+    /// Merge even if the PR isn't mergeable, CI isn't green, or a review
     /// requests changes.
     #[arg(long)]
     force: bool,