Update src/main/java/org/jenkinsci/plugins/github_branch_source/GitHubAppCredentials.java

Co-authored-by: Tim Jacomb <t.jacomb@kainos.com>

Author: bitwiseman

src/main/java/org/jenkinsci/plugins/github_branch_source/GitHubAppCredentials.java

@@ -173,7 +173,7 @@ public Secret getPassword() {
                 appInstallationToken = token.getToken();
                 long expiration;
                 try {
-                    // Adjust the token expiration to request a new token a earlier than required.
+                    // Adjust the token expiration to request a new token earlier than required.
                     // This reduces the chance that a password will be requested and then
                     // expire in the middle of a step execution
                     expiration = token.getExpiresAt().toInstant().getEpochSecond() - TOKEN_EXPIRATION_BUFFER_SECONDS;