chore(docs): #1684 Explain builder hooks in docs

Author: AlexanderArvidsson

README.md

@@ -101,13 +101,7 @@ neogit.setup {
   -- Scope persisted settings on a per-project basis
   use_per_project_settings = true,
   -- Table of settings to never persist. Uses format "Filetype--cli-value"
-  ignored_settings = {
-    "NeogitPushPopup--force-with-lease",
-    "NeogitPushPopup--force",
-    "NeogitPullPopup--rebase",
-    "NeogitCommitPopup--allow-empty",
-    "NeogitRevertPopup--no-edit",
-  },
+  ignored_settings = {},
   -- Configure highlight group features
   highlight = {
     italic = true,

doc/neogit.txt

@@ -128,13 +128,7 @@ to Neovim users.
     -- Scope persisted settings on a per-project basis
     use_per_project_settings = true,
     -- Table of settings to never persist. Uses format "Filetype--cli-value"
-    ignored_settings = {
-        "NeogitPushPopup--force-with-lease",
-        "NeogitPushPopup--force",
-        "NeogitPullPopup--rebase",
-        "NeogitCommitPopup--allow-empty",
-        "NeogitRevertPopup--no-edit",
-    },
+    ignored_settings = {},
     -- Configure highlight group features
     highlight = {
         italic = true,
@@ -2136,5 +2130,21 @@ calling the setup function:
       },
     })
 <
+
+You can also customize existing popups via the Neogit config.
+Below is an example of adding a custom switch, but you can use any function 
+from the builder API. 
+>lua
+    require("neogit").setup({
+      builders = {
+        NeogitPushPopup = function(builder)
+          builder:switch('m', 'merge_request.create', 'Create merge request', { cli_prefix = '-o ', persisted = false })
+        end,
+      },
+    })
+
+Keep in mind that builder hooks are executed at the end of the popup 
+builder, so any switches or options added will be placed at the end.
+
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 vim:tw=78:ts=8:ft=help:norl: