feat: Add custom prompt functionality to block

This commit introduces the capability for users to apply custom prompts defined in the configuration to a block. Key changes include:
- A new configuration string to store the custom prompt.
- A menu item 'Custom prompt on block'.
- Implementation of a function to apply the custom prompt to a block, mirroring the existing 'summarize block' functionality.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/App.tsx b/src/App.tsx
index 0a32968..0fb9984 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -15,6 +15,7 @@ const options = [
   'Divide into subtasks',
   'Summarize',
   'Summarize Block',
+  'Custom prompt on block',
   'Convert to flash card',
 ];