Improve `fetchFromGitLab` manual (#236111)

* doc/builders: update fetchers documentation

Co-authored-by: Valentin Gagarin <valentin.gagarin@tweag.io>

1 files changed, 7 insertions, 2 deletions

diff --git a/doc/builders/fetchers.chapter.md b/doc/builders/fetchers.chapter.md
index b86fffa46042..4d4f3f427cd4 100644
--- a/doc/builders/fetchers.chapter.md
+++ b/doc/builders/fetchers.chapter.md
@@ -132,11 +132,16 @@ A number of fetcher functions wrap part of `fetchurl` and `fetchzip`. They are m
 
 `fetchFromGitHub` expects four arguments. `owner` is a string corresponding to the GitHub user or organization that controls this repository. `repo` corresponds to the name of the software repository. These are located at the top of every GitHub HTML page as `owner`/`repo`. `rev` corresponds to the Git commit hash or tag (e.g `v1.0`) that will be downloaded from Git. Finally, `hash` corresponds to the hash of the extracted directory. Again, other hash algorithms are also available, but `hash` is currently preferred.
 
+To use a different GitHub instance, use `githubBase` (defaults to `"github.com"`).
+
 `fetchFromGitHub` uses `fetchzip` to download the source archive generated by GitHub for the specified revision. If `leaveDotGit`, `deepClone` or `fetchSubmodules` are set to `true`, `fetchFromGitHub` will use `fetchgit` instead. Refer to its section for documentation of these options.
 
 ## `fetchFromGitLab` {#fetchfromgitlab}
 
-This is used with GitLab repositories. The arguments expected are very similar to `fetchFromGitHub` above.
+This is used with GitLab repositories. It behaves similarly to `fetchFromGitHub`, and expects `owner`, `repo`, `rev`, and `hash`.
+
+To use a specific GitLab instance, use `domain` (defaults to `"gitlab.com"`).
+
 
 ## `fetchFromGitiles` {#fetchfromgitiles}
 
@@ -144,7 +149,7 @@ This is used with Gitiles repositories. The arguments expected are similar to `f
 
 ## `fetchFromBitbucket` {#fetchfrombitbucket}
 
-This is used with BitBucket repositories. The arguments expected are very similar to fetchFromGitHub above.
+This is used with BitBucket repositories. The arguments expected are very similar to `fetchFromGitHub` above.
 
 ## `fetchFromSavannah` {#fetchfromsavannah}