Remove duplicated words across docs

[eknathdj]

Summary

Removes 4 unique duplicated words, each replicated across versioned docs (v23.1 through v26.3), totaling 42 file fixes.

Fixes

#	File	Versions	Change
1	bulk-update-data.md	v23.1 - v26.3 (12)	"How to to update" → "How to update"
2	upgrade-cockroach-version.md	v24.3 - v26.3 (7)	"a cluster with with [physical cluster replication" → "with [physical cluster replication"
3	restore.md	v23.2 - v26.3 (11)	"restoring the the object" → "restoring the object"
4	orchestrate-cockroachdb-with-kubernetes-multi-cluster.md	v23.1 - v26.3 (12)	"With this this approach" → "With this approach"

All changes are doc-only, no functional impact. Each fix was manually verified as a genuine duplicate (not an intentional pattern).

This PR was generated with AI assistance (regex scan + verification).

[eknathdj]

Hi @cockroachlabs/docs-prs — could a docs-prs team member please review and approve this doc-only typo fix PR? The \pr-review\ check requires docs-prs approval for external contributors. Thank you!