CLAUDE: use verbose output in filtered tests

I observed a `./dev test pkg -f=x` scenario where no test matched, and
false success was declared.

Release note: None

Author: dhartunian

CLAUDE.md

@@ -23,15 +23,19 @@ CockroachDB is a distributed SQL database written in Go, built with Bazel and ma
 
 **Testing:**
 ```bash
-./dev test pkg/sql                    # Run unit tests for SQL package
-./dev test pkg/sql -f=TestParse      # Run specific test pattern
+./dev test pkg/sql                   # Run unit tests for SQL package
+./dev test pkg/sql -f=TestParse -v   # Run specific test pattern.
 ./dev test pkg/sql --race            # Run with race detection
 ./dev test pkg/sql --stress          # Run repeatedly until failure
 ./dev testlogic                      # Run all SQL logic tests
 ./dev testlogic ccl                  # Run enterprise logic tests
 ./dev testlogic --files='prepare|fk' # Run specific test files
 ```
 
+Note that when filtering tests via `-f` to include the `-v` flag which
+will warn you in the output if your filter didn't match anything. Look
+for `testing: warning: no tests to run` in the output.
+
 **Code Generation and Linting:**
 ```bash
 ./dev generate            # Generate all code (protobuf, parsers, etc.)
@@ -129,4 +133,4 @@ Always run `./dev generate` after modifying `.proto` files, SQL grammar, or opti
   - Require the user to specify an epic number (or None) which should be included at the bottom of the commit record following "Epic:".
   - Prefix the subject line with the package in which the bulk of the changes occur.
   - For multi-commit PRs, summarize each commit in the PR record.
-  - Do not include a test plan unless explicitly asked by the user.
+  - Do not include a test plan unless explicitly asked by the user.