Properly encode audit log/ban reasons

lib/Client.js

@@ -110,6 +110,7 @@ class Client extends EventEmitter {
     * @arg {Object} [options.rest] Options for the REST request handler
     * @arg {Object} [options.rest.agent] A HTTPS Agent used to proxy requests
     * @arg {String} [options.rest.baseURL] The base URL to use for API requests. Defaults to `/api/v${REST_VERSION}`
+    * @arg {Boolean} [options.rest.decodeReasons=true] [DEPRECATED] Whether reasons should be decoded with `decodeURIComponent()` when making REST requests. This is true by default to mirror pre-0.15.0 behavior (where reasons were expected to be URI-encoded), and should be set to false once your bot code stops. Reasons will no longer be decoded in the future
     * @arg {Boolean} [options.rest.disableLatencyCompensation=false] Whether to disable the built-in latency compensator or not
     * @arg {String} [options.rest.domain="discord.com"] The domain to use for API requests
     * @arg {Number} [options.rest.latencyThreshold=30000] The average request latency at which Eris will start emitting latency errors

lib/rest/RequestHandler.js

@@ -24,6 +24,7 @@ class RequestHandler {
         this.options = options = Object.assign({
             agent: client.options.agent || null,
             baseURL: Endpoints.BASE_URL,
+            decodeReasons: true,
             disableLatencyCompensation: false,
             domain: "discord.com",
             latencyThreshold: client.options.latencyThreshold || 30000,
@@ -92,9 +93,21 @@ class RequestHandler {
                         headers.Authorization = this._client._token;
                     }
                     if(body && body.reason) { // Audit log reason sniping
-                        headers["X-Audit-Log-Reason"] = body.reason;
+                        let unencodedReason = body.reason;
+                        if(this.options.decodeReasons) {
+                            try {
+                                if(unencodedReason.includes("%") && !unencodedReason.includes(" ")) {
+                                    unencodedReason = decodeURIComponent(unencodedReason);
+                                }
+                            } catch(err) {
+                                this._client.emit("error", err);
+                            }
+                        }
+                        headers["X-Audit-Log-Reason"] = encodeURIComponent(unencodedReason);
                         if((method !== "PUT" || !url.includes("/bans")) && (method !== "POST" || !url.includes("/prune"))) {
                             delete body.reason;
+                        } else {
+                            body.reason = unencodedReason;
                         }
                     }
                     if(file) {