Fix a typo in the multi buffers documentation (#18535)

Closes #18533

Release Notes:

- N/A

docs/src/multibuffers.md

@@ -31,7 +31,7 @@ To start a search run the `pane: Toggle Search` command (`cmd-shift-f` on macOS,
 
 ## Diagnostics
 
-If you have a language server installed, the diagnostics pane can show you all errors across your project. You can open it by clicking on the icon in the status bar, or running the `diagnostcs: Deploy` command` ('cmd-shift-m` on macOS, `ctrl-shift-m` on Windows/Linux, or `:clist` in Vim mode).
+If you have a language server installed, the diagnostics pane can show you all errors across your project. You can open it by clicking on the icon in the status bar, or running the `diagnostics: Deploy` command` ('cmd-shift-m` on macOS, `ctrl-shift-m` on Windows/Linux, or `:clist` in Vim mode).
 
 ## Find References