[dds/dap] Fix typos in DAP readme

Change-Id: Ib2d7b3ce14d3b337a7612eb1c1b1da4a76a7fef9
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/308100
Reviewed-by: Ben Konyi <bkonyi@google.com>

Author: DanTup

pkg/dds/tool/dap/README.md

@@ -47,9 +47,9 @@ Arguments specific to `launchRequest` are:
 Arguments specific to `attachRequest` are:
 
 - `String vmServiceInfoFile` - the file to read the VM Service info from \*
-- `String vmServiceInfoFile` - the VM Service URI to attach to \*
+- `String vmServiceUri` - the VM Service URI to attach to \*
 
-\* Exactly one of `vmServiceInfoFile` or `vmServiceInfoFile` should be supplied.
+\* Exactly one of `vmServiceInfoFile` or `vmServiceUri` should be supplied.
 
 ## Expression Evaluation Format Specifiers