docs: update feegrant `AllowedFeeAllowance` docs (#11344)

## Description

Closes: #11346



---

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### Reviewers Checklist

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your handle next to the items reviewed if you only reviewed selected items.*

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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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proto/cosmos/feegrant/v1beta1/feegrant.proto

@@ -58,7 +58,7 @@ message AllowedMsgAllowance {
   option (gogoproto.goproto_getters)         = false;
   option (cosmos_proto.implements_interface) = "FeeAllowanceI";
 
-  // allowance can be any of basic and filtered fee allowance.
+  // allowance can be any of basic and periodic fee allowance.
   google.protobuf.Any allowance = 1 [(cosmos_proto.accepts_interface) = "FeeAllowanceI"];
 
   // allowed_messages are the messages for which the grantee has the access.
@@ -73,6 +73,6 @@ message Grant {
   // grantee is the address of the user being granted an allowance of another user's funds.
   string grantee = 2 [(cosmos_proto.scalar) = "cosmos.AddressString"];
 
-  // allowance can be any of basic and filtered fee allowance.
+  // allowance can be any of basic, periodic, allowed fee allowance.
   google.protobuf.Any allowance = 3 [(cosmos_proto.accepts_interface) = "FeeAllowanceI"];
 }

proto/cosmos/feegrant/v1beta1/tx.proto

@@ -31,7 +31,7 @@ message MsgGrantAllowance {
   // grantee is the address of the user being granted an allowance of another user's funds.
   string grantee = 2 [(cosmos_proto.scalar) = "cosmos.AddressString"];
 
-  // allowance can be any of basic and filtered fee allowance.
+  // allowance can be any of basic, periodic, allowed fee allowance.
   google.protobuf.Any allowance = 3 [(cosmos_proto.accepts_interface) = "FeeAllowanceI"];
 }
 

x/feegrant/feegrant.pb.go

@@ -179,7 +179,7 @@ func (m *PeriodicAllowance) GetPeriodReset() time.Time {
 
 // AllowedMsgAllowance creates allowance only for specified message types.
 type AllowedMsgAllowance struct {
-	// allowance can be any of basic and filtered fee allowance.
+	// allowance can be any of basic and periodic fee allowance.
 	Allowance *types1.Any `protobuf:"bytes,1,opt,name=allowance,proto3" json:"allowance,omitempty"`
 	// allowed_messages are the messages for which the grantee has the access.
 	AllowedMessages []string `protobuf:"bytes,2,rep,name=allowed_messages,json=allowedMessages,proto3" json:"allowed_messages,omitempty"`
@@ -224,7 +224,7 @@ type Grant struct {
 	Granter string `protobuf:"bytes,1,opt,name=granter,proto3" json:"granter,omitempty"`
 	// grantee is the address of the user being granted an allowance of another user's funds.
 	Grantee string `protobuf:"bytes,2,opt,name=grantee,proto3" json:"grantee,omitempty"`
-	// allowance can be any of basic and filtered fee allowance.
+	// allowance can be any of basic, periodic, allowed fee allowance.
 	Allowance *types1.Any `protobuf:"bytes,3,opt,name=allowance,proto3" json:"allowance,omitempty"`
 }
 

x/feegrant/spec/01_concepts.md

@@ -20,6 +20,7 @@ There are two types of fee allowances present at the moment:
 
 * `BasicAllowance`
 * `PeriodicAllowance`
+* `AllowedMsgAllowance`
 
 ## BasicAllowance
 
@@ -49,6 +50,16 @@ There are two types of fee allowances present at the moment:
 
 * `period_reset` keeps track of when a next period reset should happen.
 
+## AllowedMsgAllowance
+
+`AllowedMsgAllowance` is a fee allowance, it can be any of `BasicFeeAllowance`, `PeriodicAllowance` but restricted only to the allowed messages mentioned by the granter.
+
++++ https://github.com/cosmos/cosmos-sdk/blob/691032b8be0f7539ec99f8882caecefc51f33d1f/proto/cosmos/feegrant/v1beta1/feegrant.proto#L55-L65
+
+* `allowance` is either `BasicAllowance` or `PeriodicAllowance`.
+
+* `allowed_messages` is array of messages allowed to execute the given allowance.
+
 ## FeeGranter flag
 
 `feegrant` module introduces a `FeeGranter` flag for CLI for the sake of executing transactions with fee granter. When this flag is set, `clientCtx` will append the granter account address for transactions generated through CLI.

x/feegrant/tx.pb.go

@@ -37,7 +37,7 @@ type MsgGrantAllowance struct {
 	Granter string `protobuf:"bytes,1,opt,name=granter,proto3" json:"granter,omitempty"`
 	// grantee is the address of the user being granted an allowance of another user's funds.
 	Grantee string `protobuf:"bytes,2,opt,name=grantee,proto3" json:"grantee,omitempty"`
-	// allowance can be any of basic and filtered fee allowance.
+	// allowance can be any of basic, periodic, allowed fee allowance.
 	Allowance *types.Any `protobuf:"bytes,3,opt,name=allowance,proto3" json:"allowance,omitempty"`
 }