Add recommendation for separate indexes per repository

- Updated README.md and doc/zoekt.txt to recommend using separate index paths for each repository
- This prevents search results from mixing across different projects
- Eliminates the need for repo: filters in search queries

Author: jupblb

README.md

@@ -82,6 +82,12 @@ require("zoekt").setup({
 })
 ```
 
+**Recommendation**: For better search isolation, consider using separate index
+paths for each repository. This prevents search results from mixing across
+different projects and eliminates the need for `repo:` filters in your queries.
+You can set a custom `index_path` per project or use environment variables to
+manage multiple indexes.
+
 ## Usage
 
 ### Commands

doc/zoekt.txt

@@ -166,6 +166,13 @@ You can configure different index paths for different projects: >lua
   :ZoektSearch handleAuth
 <
 
+Recommendation: Use separate index paths for each repository to prevent
+search results from mixing across different projects. This eliminates the
+need for `repo:` filters in your queries. You can achieve this by:
+- Setting a custom `index_path` in your project-specific config
+- Using environment variables (e.g., `ZOEKT_INDEX_PATH`)
+- Creating a `.nvim.lua` file in each project with custom settings
+
 Environment Variables ~
 
 Set `ZOEKT_INDEX_PATH` to override the default index location: >bash