[docs] x/crisis - general audit and cleanup (#8269)

* update docs

* review changes

Co-authored-by: atheeshp <59333759+atheeshp@users.noreply.github.com>

x/crisis/spec/01_state.md

@@ -14,5 +14,5 @@ with the standard gas consumption method.
 
 The ConstantFee param is held in the global params store. 
 
- - Params: `mint/params -> amino(sdk.Coin)`
+ - Params: `mint/params -> legacy_amino(sdk.Coin)`
 

x/crisis/spec/02_messages.md

@@ -11,12 +11,7 @@ corresponding updates to the state.
 
 Blockchain invariants can be checked using the `MsgVerifyInvariant` message. 
 
-```go
-type MsgVerifyInvariant struct {
-	Sender         sdk.AccAddress 
-	InvariantRoute string
-}
-```
++++ https://github.com/cosmos/cosmos-sdk/blob/v0.40.0-rc7/proto/cosmos/crisis/v1beta1/tx.proto#L14-L22
 
 This message is expected to fail if: 
  - the sender does not have enough coins for the constant fee