Add a section about navigating within multibuffers (zed-industries#14979

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Release Notes:

- N/A

docs/src/multibuffers.md

@@ -19,6 +19,12 @@ When in a multibuffer, it is often useful to use multiple cursors to edit every
 
 When you want to edit all matches you can select them by running the `editor: Select All Matches` command (`cmd-shift-l` on macOS, `ctrl-shift-l` on Windows/Linux, or `g a` in Vim mode).
 
+## Navigating to the Source File
+
+While you can easily edit files in a multibuffer, navigating directly to the source file is often beneficial. You can accomplish this by clicking on any of the divider lines between excerpts or by placing your cursor in an excerpt and executing the `editor: open excerpts` command. It’s key to note that if multiple cursors are being used, the command will open the source file positioned under each cursor within the multibuffer.
+
+Additionally, if you prefer to use the mouse and would like to double-click on an excerpt to open it, you can enable this functionality with the setting: `"double_click_in_multibuffer": "open"`.
+
 ## Project search
 
 To start a search run the `pane: Toggle Search` command (`cmd-shift-f` on macOS, `ctrl-shift-f` on Windows/Linux, or `g/` in Vim mode). After the search has completed, the results will be shown in a new multibuffer. There will be one excerpt for each matching line across the whole project.