docs: remove invalid example about mixing files and directory (#4566)

Author: ldez

docs/src/docs/welcome/quick-start.mdx

@@ -14,13 +14,16 @@ It's an equivalent of executing:
 golangci-lint run ./...
 ```
 
-You can choose which directories and files to analyze:
+You can choose which directories or files to analyze:
 
 ```sh
-golangci-lint run dir1 dir2/... dir3/file1.go
+golangci-lint run dir1 dir2/...
+golangci-lint run file1.go
 ```
 
-Directories are NOT analyzed recursively. To analyze them recursively append `/...` to their path.
+Directories are NOT analyzed recursively.
+To analyze them recursively append `/...` to their path.
+It's not possible to mix files and packages/directories, and files must come from the same package.
 
 GolangCI-Lint can be used with zero configuration. By default, the following linters are enabled: