Merge pull request JuliaLang#22564 from JuliaLang/ksh/docpushopt

Document fields of PushOptions

base/libgit2/types.jl

@@ -393,6 +393,18 @@ end
     LibGit2.PushOptions
 
 Matches the [`git_push_options`](https://libgit2.github.com/libgit2/#HEAD/type/git_push_options) struct.
+
+The fields represent:
+  * `version`: version of the struct in use, in case this changes later. For now, always `1`.
+  * `parallelism`: if a pack file must be created, this variable sets the number of worker
+     threads which will be spawned by the packbuilder. If `0`, the packbuilder will auto-set
+     the number of threads to use. The default is `1`.
+  * `callbacks`: the callbacks (e.g. for authentication with the remote) to use for the push.
+  * `proxy_opts`: only relevant if the LibGit2 version is greater than or equal to `0.25.0`.
+     Sets options for using a proxy to communicate with a remote. See [`ProxyOptions`](@ref)
+     for more information.
+  * `custom_headers`: only relevant if the LibGit2 version is greater than or equal to `0.24.0`.
+     Extra headers needed for the push operation.
 """
 @kwdef struct PushOptions
     version::Cuint                     = 1