feat(copilotchat): change mapping prefix to <Leader>C

For some reason, this doesn't actually work.  Tried a few other
approaches that didn't work either.  Committing the preferred
non-working approach as a reminder to revisit this.

Author: nisavid

lua/community.lua

@@ -78,6 +78,19 @@ return {
   { import = "astrocommunity.editing-support.copilotchat-nvim" },
   {
     "CopilotC-Nvim/CopilotChat.nvim",
+    dependencies = {
+      {
+        "AstroNvim/astrocore",
+        opts = {
+          options = {
+            g = {
+              -- FIXME: This doesn't actually work
+              copilot_chat_prefix = "<Leader>C",
+            },
+          },
+        },
+      },
+    },
     opts = {
       model = "claude-3.7-sonnet-thought",
     },