docs: clarify language about censor threshold as one third + 1 (#11843)

## Description

Documentation fix to clarify censorship threshold language. This came up because the "No with Veto" proposal justification involves censorship at 1/3 + 1 voting power. See https://github.com/cosmos/governance/pull/32

---

### Author Checklist

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- [ ] included the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [ ] added `!` to the type prefix if API or client breaking change
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- [ ] added a changelog entry to `CHANGELOG.md`
- [ ] included comments for [documenting Go code](https://blog.golang.org/godoc)
- [ ] updated the relevant documentation or specification
- [ ] reviewed "Files changed" and left comments if necessary
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- [ ] confirmed the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [ ] confirmed `!` in the type prefix if API or client breaking change
- [ ] confirmed all author checklist items have been addressed 
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- [ ] reviewed tests and test coverage
- [ ] manually tested (if applicable)

x/gov/spec/01_concepts.md

@@ -163,7 +163,7 @@ If a delegator does not vote, it will inherit its validator vote.
 * If the delegator votes after its validator, it will override its validator
   vote with its own. If the proposal is urgent, it is possible
   that the vote will close before delegators have a chance to react and
-  override their validator's vote. This is not a problem, as proposals require more than 2/3rd of the total voting power to pass before the end of the voting period. If more than 2/3rd of validators collude, they can censor the votes of delegators anyway.
+  override their validator's vote. This is not a problem, as proposals require more than 2/3rd of the total voting power to pass before the end of the voting period. Because as little as 1/3 + 1 validation power could collude to censor transactions, non-collusion is already assumed for ranges exceeding this threshold.
 
 ### Validator’s punishment for non-voting