reword documentation for git.autoForwardBranches (#4545)

- **PR Description**

The wording "lazygit will automatically forward branches to their
upstream after fetching" could be interpreted to mean that lazygit
automatically pushes branches, rather than operating locally. Edited to
make the behavior more clear.

- **Please check if the PR fulfills these requirements**

* [x] Cheatsheets are up-to-date (run `go generate ./...`)
* [x] Code has been formatted (see
[here](https://github.com/jesseduffield/lazygit/blob/master/CONTRIBUTING.md#code-formatting))
* [ ] Tests have been added/updated (see
[here](https://github.com/jesseduffield/lazygit/blob/master/pkg/integration/README.md)
for the integration test guide)
* [ ] Text is internationalised (see
[here](https://github.com/jesseduffield/lazygit/blob/master/CONTRIBUTING.md#internationalisation))
* [ ] If a new UserConfig entry was added, make sure it can be
hot-reloaded (see
[here](https://github.com/jesseduffield/lazygit/blob/master/docs/dev/Codebase_Guide.md#using-userconfig))
* [x] Docs have been updated if necessary
* [x] You've read through your own file changes for silly mistakes etc

<!--
Be sure to name your PR with an imperative e.g. 'Add worktrees view'
see https://github.com/jesseduffield/lazygit/releases/tag/v0.40.0 for
examples
-->

docs/Config.md

@@ -337,7 +337,7 @@ git:
   # If true, periodically refresh files and submodules
   autoRefresh: true
 
-  # If not "none", lazygit will automatically forward branches to their upstream after fetching. Applies to branches that are not the currently checked out branch, and only to those that are strictly behind their upstream (as opposed to diverged).
+  # If not "none", lazygit will automatically fast-forward local branches to match their upstream after fetching. Applies to branches that are not the currently checked out branch, and only to those that are strictly behind their upstream (as opposed to diverged).
   # Possible values: 'none' | 'onlyMainBranches' | 'allBranches'
   autoForwardBranches: onlyMainBranches
 

pkg/config/user_config.go

@@ -244,7 +244,7 @@ type GitConfig struct {
 	AutoFetch bool `yaml:"autoFetch"`
 	// If true, periodically refresh files and submodules
 	AutoRefresh bool `yaml:"autoRefresh"`
-	// If not "none", lazygit will automatically forward branches to their upstream after fetching. Applies to branches that are not the currently checked out branch, and only to those that are strictly behind their upstream (as opposed to diverged).
+	// If not "none", lazygit will automatically fast-forward local branches to match their upstream after fetching. Applies to branches that are not the currently checked out branch, and only to those that are strictly behind their upstream (as opposed to diverged).
 	// Possible values: 'none' | 'onlyMainBranches' | 'allBranches'
 	AutoForwardBranches string `yaml:"autoForwardBranches" jsonschema:"enum=none,enum=onlyMainBranches,enum=allBranches"`
 	// If true, pass the --all arg to git fetch

schema/config.json

@@ -331,7 +331,7 @@
             "onlyMainBranches",
             "allBranches"
           ],
-          "description": "If not \"none\", lazygit will automatically forward branches to their upstream after fetching. Applies to branches that are not the currently checked out branch, and only to those that are strictly behind their upstream (as opposed to diverged).\nPossible values: 'none' | 'onlyMainBranches' | 'allBranches'",
+          "description": "If not \"none\", lazygit will automatically fast-forward local branches to match their upstream after fetching. Applies to branches that are not the currently checked out branch, and only to those that are strictly behind their upstream (as opposed to diverged).\nPossible values: 'none' | 'onlyMainBranches' | 'allBranches'",
           "default": "onlyMainBranches"
         },
         "fetchAll": {