update main<->docs merge instructions in CONTRIBUTING.md

Author: cspotcode

CONTRIBUTING.md

@@ -44,9 +44,12 @@ This site was used to generate the favicon from a high-res PNG export of the SVG
 
 ## Release checklist
 
-1. Merge `docs` into `main`
+1. Merge `docs` into `main` using a pull request, ensuring a consistent squash-merge
 2. Rebuild the README (see instructions above, necessary because npmjs.com renders the readme)
 3. Publish with `np`
 4. Add changelog to the Github Release; match formatting from previous releases
-5. Merge `main` into `docs` (this automatically rebuilds the website)
+5. Move `docs` branch to head of `main`
+  - this rebuilds the website
+  - `git push --force origin main:docs`
+  - avoids merge messiness due to earlier squash-merge from `docs` to `main`
 6. If tsconfig schema has changed, send a pull request to schemastore.  [Example](https://github.com/SchemaStore/schemastore/pull/1208)