Merge branch 'docs-feature-flag-alert-box' into 'master'

Update alert box text

See merge request gitlab-org/gitlab!40473

doc/development/documentation/feature_flags.md

@@ -66,7 +66,7 @@ be enabled for a single project, and is not ready for production use:
 > - It's not recommended for production use.
 > - To use it in GitLab self-managed instances, ask a GitLab administrator to [enable it](#anchor-to-section). **(CORE ONLY)**
 
-CAUTION: **Warning:**
+CAUTION: **Caution:**
 This feature might not be available to you. Check the **version history** note above for details.
 
 (...Regular content goes here...)
@@ -125,7 +125,7 @@ use:
 > - It's recommended for production use.
 > - For GitLab self-managed instances, GitLab administrators can opt to [disable it](#anchor-to-section). **(CORE ONLY)**
 
-CAUTION: **Warning:**
+CAUTION: **Caution:**
 This feature might not be available to you. Check the **version history** note above for details.
 
 (...Regular content goes here...)
@@ -181,7 +181,7 @@ cannot be enabled for a single project, and is ready for production use:
 > - It's recommended for production use.
 > - For GitLab self-managed instances, GitLab administrators can opt to [disable it](#anchor-to-section). **(CORE ONLY)**
 
-CAUTION: **Warning:**
+CAUTION: **Caution:**
 This feature might not be available to you. Check the **version history** note above for details.
 
 (...Regular content goes here...)
@@ -254,7 +254,7 @@ be enabled by project, and is ready for production use:
 > - It's recommended for production use.
 > - For GitLab self-managed instances, GitLab administrators can opt to [disable it](#anchor-to-section). **(CORE ONLY)**
 
-CAUTION: **Warning:**
+CAUTION: **Caution:**
 This feature might not be available to you. Check the **version history** note above for details.
 
 (...Regular content goes here...)