feat!: x/gov: raise max description length to 10k chars (backport #10740) (#10921)

* feat!: x/gov: raise max description length to 10k chars (#10740)

The 5k character limit for governance proposals is something I've ran into several times now. This feels like an artificial constraint. The deposit is our mechanism to combat spam, and extra state used for this is really not a problem.

In this PR I propose raising this limit to 10k characters, to remove much of the immediate need for working around this 5k limit.

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## Description

Closes: #XXXX

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---

### Author Checklist

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I have...

- [x] included the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [x] added `!` to the type prefix if API or client breaking change
- [x] targeted the correct branch (see [PR Targeting](https://github.com/cosmos/cosmos-sdk/blob/master/CONTRIBUTING.md#pr-targeting))
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- [x] followed the guidelines for [building modules](https://github.com/cosmos/cosmos-sdk/blob/master/docs/building-modules)
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- [x] added a changelog entry to `CHANGELOG.md`
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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
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- [ ] manually tested (if applicable)

(cherry picked from commit ea2bcc8adf)

# Conflicts:
#	CHANGELOG.md

* Update CHANGELOG.md

* Update CHANGELOG.md

Co-authored-by: Dev Ojha <ValarDragon@users.noreply.github.com>
Co-authored-by: Robert Zaremba <robert@zaremba.ch>

CHANGELOG.md

@@ -43,6 +43,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 * (auth) [\#10536](https://github.com/cosmos/cosmos-sdk/pull/10536]) Enable `SetSequence` for `ModuleAccount`.
 * (store) [#10218](https://github.com/cosmos/cosmos-sdk/pull/10218) Charge gas even when there are no entries while seeking.
 * (store) [#10247](https://github.com/cosmos/cosmos-sdk/pull/10247) Charge gas for the key length in gas meter.
+* (x/gov) [\#10740](https://github.com/cosmos/cosmos-sdk/pull/10740) Increase maximum proposal description size from 5k characters to 10k characters.
 
 ### API Breaking Changes
 

x/gov/types/content.go

@@ -9,7 +9,7 @@ import (
 
 // Constants pertaining to a Content object
 const (
-	MaxDescriptionLength int = 5000
+	MaxDescriptionLength int = 10000
 	MaxTitleLength       int = 140
 )