Improve Dispatch Errors (#878)

* better dispatch errors

* dry_run to use same DispatchError

* fix dry_run_fails; use correct transfer amount

* Hide ModuleError impl and avoid pulling details from metadata unless user needs them

* fix tests

* actually fix the tests (hopefully..)

* Add a couple more DispatchError test cases

* Add a comment about where the error was copied from

* Also expose a way to obtain the raw module error data

* Remove redundant variant prefixes

* explicit lifetime on From<str> for clarity

* fmt

subxt/src/blocks/block_types.rs

@@ -72,7 +72,7 @@ where
         let block_hash = self.header.hash();
         let block_details = match self.client.rpc().block(Some(block_hash)).await? {
             Some(block) => block,
-            None => return Err(BlockError::block_hash_not_found(block_hash).into()),
+            None => return Err(BlockError::not_found(block_hash).into()),
         };
 
         Ok(BlockBody::new(

subxt/src/blocks/blocks_client.rs

@@ -66,7 +66,7 @@ where
 
             let block_header = match client.rpc().header(Some(block_hash)).await? {
                 Some(header) => header,
-                None => return Err(BlockError::block_hash_not_found(block_hash).into()),
+                None => return Err(BlockError::not_found(block_hash).into()),
             };
 
             Ok(Block::new(block_header, client))