Update monorepo scanning with historical secrets note (#1945)

* "version" doesn't make much sense

* Blurb about turning off historical secrets

Author: sinat101

docs/kb/semgrep-ci/scan-monorepo-in-parts.md

@@ -15,6 +15,10 @@ As such, it can be helpful to scan a monorepo in parts for multiple reasons:
 * To improve scan performance in CI and reduce CI run times
 * To logically split the monorepo to simplify managing findings
 
+:::note
+Historical secrets scanning relies on examining the entire repo commit history and cannot be split up by path as other scan types like Code, Supply Chain, or Secrets. As such, it is recommended to turn off historical secrets when splitting up a monorepo by path.
+:::
+
 ## How to configure Semgrep in CI to split up a monorepo
 
 When scanning a repo with Semgrep in CI, the base command is `semgrep ci`. To understand this default setup for your source code manager (SCM) and CI provider, see [Getting started with Semgrep in continuous integration (CI)](/deployment/add-semgrep-to-ci).
@@ -42,7 +46,7 @@ For example:
 SEMGREP_REPO_DISPLAY_NAME=monorepo/moduleA semgrep ci --subdir src/moduleA/
 ```
 
-It is important that scans of different versions never have the same `SEMGREP_REPO_DISPLAY_NAME`. This is necessary to ensure findings have a consistent status and is helpful for developers and security engineers to understand which findings pertain to the module that they are responsible for.
+It is important that scans of different modules never have the same `SEMGREP_REPO_DISPLAY_NAME`. This is necessary to ensure findings have a consistent status and is helpful for developers and security engineers to understand which findings pertain to the module that they are responsible for.
 
 To scan the entire monorepo, trigger one scan for each module.