docs: README.md groups add syntax contradicts actual CLI behavior

[athoune]

Bug

The README.md documentation for codesearch groups add shows an incorrect syntax that does not match the actual CLI implementation.

README.md (lines 356-357) — incorrect

codesearch groups add my-group repo1 repo2 repo3

This suggests positional arguments for group name + members.

Actual CLI behavior

$ codesearch groups add columns datafusion
error: unexpected argument 'datafusion' found

Usage: codesearch groups add [OPTIONS] <NAME>

The CLI only accepts a single positional argument (the group name). Members must be added via the --aliases flag:

codesearch groups add my-group --aliases repo1 repo2 repo3

Proposed fix

Update the README.md section "Groups" (around line 356) to reflect the correct syntax:

codesearch groups add my-group --aliases repo1 repo2 repo3

This matches the --help output:

-a, --aliases <ALIASES>...  Aliases to include in the group (space-separated)