Automatically clear copilot diagnostics on asking new question

Closes #362

Signed-off-by: Tomas Slusny <[email protected]>

lua/CopilotChat/config.lua

@@ -119,7 +119,6 @@ return {
     Review = {
       prompt = '/COPILOT_REVIEW Review the selected code.',
       callback = function(response, source)
-        local ns = vim.api.nvim_create_namespace('copilot_review')
         local diagnostics = {}
         for line in response:gmatch('[^\r\n]+') do
           if line:find('^line=') then
@@ -152,7 +151,11 @@ return {
             end
           end
         end
-        vim.diagnostic.set(ns, source.bufnr, diagnostics)
+        vim.diagnostic.set(
+          vim.api.nvim_create_namespace('copilot_diagnostics'),
+          source.bufnr,
+          diagnostics
+        )
       end,
     },
     Fix = {

lua/CopilotChat/init.lua

@@ -387,6 +387,8 @@ function M.ask(prompt, config, source)
 
   M.open(config, source)
 
+  vim.diagnostic.reset(vim.api.nvim_create_namespace('copilot_diagnostics'))
+
   if config.clear_chat_on_new_prompt then
     M.stop(true, config)
   end

lua/CopilotChat/prompts.lua

@@ -90,6 +90,8 @@ line=<start_line>-<end_line>: <issue_description>
   
 If you find multiple issues on the same line, list each issue separately within the same feedback statement, using a semicolon to separate them.
 
+At the end of your review, add this: "**`To clear buffer highlights, please ask a different question.`**".
+
 Example feedback:
 line=3: The variable name 'x' is unclear. Comment next to variable declaration is unnecessary.
 line=8: Expression is overly complex. Break down the expression into simpler components.