update contributing

CONTRIBUTING.md

@@ -47,11 +47,15 @@ contributors, the general procedure for contributing has been established:
       to begin work.
 5. To submit your work as a contribution to the repository follow standard GitHub best practices. See [pull request guideline](#pull-requests) below.
 
-**Note:** For very small or blatantly obvious problems such as typos, you are
+**Note:** For very small or blatantly obvious problems, you are
 not required to an open issue to submit a PR, but be aware that for more complex
 problems/features, if a PR is opened before an adequate design discussion has
 taken place in a GitHub issue, that PR runs a high likelihood of being rejected.
 
+**Note 2:** At this time, we will not be accepting contributions that only fix spelling
+or grammar errors in documentation, code or elsewhere. The repository has a nightly job that
+spell checks all files and will automatically open PRs for any spelling errors.
+
 ## Teams Dev Calls
 
 The Cosmos SDK has many stakeholders contributing and shaping the project. The Core SDK team is composed of Interchain GmbH and Regen Network Development developers. Any long-term contributors and additional maintainers from other projects are welcome. We use self-organizing principles to coordinate and collaborate across organizations in structured "EPIC" that focus on specific problem domains or architectural components of the Cosmos SDK.