docs(gov): improve gov module spec (#9681)

## Description

Updating the spec to follow the implementation

ref: cosmos/cosmos-sdk#9519 (review)


---

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- [ ] added a changelog entry to `CHANGELOG.md`
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- [x] confirmed `!` in the type prefix if API or client breaking change
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x/gov/spec/01_concepts.md

@@ -56,11 +56,14 @@ arbitrary state changes.
 
 ## Deposit
 
-To prevent spam, proposals must be submitted with a deposit in the coins defined in the `MinDeposit` param. The voting period will not start until the proposal's deposit equals `MinDeposit`.
+To prevent spam, proposals must be submitted with a deposit in the coins defined in the `MinDeposit` param.
 
-When a proposal is submitted, it has to be accompanied by a deposit that must be strictly positive, but can be inferior to `MinDeposit`. The submitter doesn't need to pay for the entire deposit on their own. If a proposal's deposit is inferior to `MinDeposit`, other token holders can increase the proposal's deposit by sending a `Deposit` transaction. The deposit is kept in an escrow in the governance `ModuleAccount` until the proposal is finalized (passed or rejected).
+When a proposal is submitted, it has to be accompanied with a deposit that must be strictly positive, but can be inferior to `MinDeposit`. The submitter doesn't need to pay for the entire deposit on their own.
+The newly created proposal is stored in an _inactive proposal queue_ and stays there until its deposit passes the `MinDeposit`. Other token holders can increase the proposal's deposit by sending a `Deposit` transaction.
+If a proposal doesn't pass the `MinDeposit` before the deposit end time (the time when deposits are no longer accepted), the proposal will be destroyed: the proposal will be removed from state and the deposit will be burned (see x/gov `EndBlocker`).
+When a proposal deposit passes the `MinDeposit` threshold (even during the proposal submission) before the deposit end time, the proposal will be moved into the _active proposal queue_ and the voting period will begin.
 
-Once the proposal's deposit reaches `MinDeposit`, it enters voting period. If proposal's deposit does not reach `MinDeposit` before `MaxDepositPeriod`, proposal closes and nobody can deposit on it anymore.
+The deposit is kept in escrow and held by the governance `ModuleAccount` until the proposal is finalized (passed or rejected).
 
 ### Deposit refund and burn