Add a setting to control the number of context lines in excerpts (#37138)

Fixes https://github.com/zed-industries/zed/discussions/28739

Release Notes:

- Added a setting, `excerpt_context_lines`, for setting the number of
context lines shown in a multibuffer

docs/src/configuring-zed.md

@@ -1461,6 +1461,16 @@ This setting enables integration with macOS’s native window tabbing feature. W
 
 Positive `integer` values
 
+## Excerpt Context Lines
+
+- Description: The number of lines of context to provide when showing excerpts in the multibuffer.
+- Setting: `excerpt_context_lines`
+- Default: `2`
+
+**Options**
+
+Positive `integer` value between 1 and 32. Values outside of this range will be clamped to this range.
+
 ## Extend Comment On Newline
 
 - Description: Whether to start a new line with a comment when a previous line is a comment as well.

docs/src/development/releases.md

@@ -51,7 +51,6 @@ Credentials for various services used in this process can be found in 1Password.
    - We sometimes correct things here and there that didn't translate from GitHub's renderer to Kit's.
 
 1. Build social media posts based on the popular items in stable.
-
    - You can use the [prior week's post chain](https://zed.dev/channel/tweets-23331) as your outline.
    - Stage the copy and assets using [Buffer](https://buffer.com), for both X and BlueSky.
    - Publish both, one at a time, ensuring both are posted to each respective platform.
@@ -89,7 +88,6 @@ You will need write access to the Zed repository to do this:
    - Download the artifacts for each release draft and test that you can run them locally.
 
 1. Publish stable / preview drafts, one at a time.
-
    - Use [Vercel](https://vercel.com/zed-industries/zed-dev) to check the progress of the website rebuild.
      The release will be public once the rebuild has completed.
 

docs/src/visual-customization.md

@@ -334,7 +334,9 @@ TBD: Centered layout related settings
 ```json
 {
   // The default number of lines to expand excerpts in the multibuffer by.
-  "expand_excerpt_lines": 5
+  "expand_excerpt_lines": 5,
+  // The default number of lines of context provided for excerpts in the multibuffer by.
+  "excerpt_context_lines": 2
 }
 ```