Turn off git's message about default branch name in deploydocs.jl (#2854)

Author: abhro

CHANGELOG.md

@@ -9,6 +9,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 * Added `Remotes.Forgejo` for specifying a `Remote` hosted on a Forgejo instance (such as codeberg.org). ([#2857])
 
+### Changed
+
+* Git no longer displays a message about the default branch name when calling `deploydocs()`. ([#2854])
+
 ## Version [v1.16.1] - 2025-11-21
 
 ### Fixed

src/deploydocs.jl

@@ -379,7 +379,7 @@ function git_push(
     # Generate a closure with common commands for ssh and https
     function git_commands(sshconfig = nothing)
         # Setup git.
-        run(`$(git()) init`)
+        run(`$(git()) init --initial-branch=main`) # specify initial branch just to turn off the advice in the deploy logs
         run(`$(git()) config user.name "Documenter.jl"`)
         run(`$(git()) config user.email "documenter@juliadocs.github.io"`)
         run(`$(git()) config commit.gpgsign false`)