Should error on the duplicated entry

[himself65]

See: https://github.com/himself65/bunchee-issue-593

> @llamaindex/[email protected] build
> bunchee

Exports                     File                                          Size
.                           dist/index.cjs                                468 kB
                            dist/index.js                                 466 kB
                            dist/index.d.ts                               3.04 kB
                            dist/index.d.cts                              3.04 kB
. (browser)                 dist/index.browser.js                         479 kB
                            dist/index.browser.d.ts                       2.31 kB
. (edge-light)              dist/index.edge-light.js                      479 kB
                            dist/index.edge-light.d.ts                    3.09 kB
. (workerd)                 dist/index.workerd.js                         477 kB
                            dist/index.workerd.d.ts                       3.09 kB
./multi-model (browser)     multi-model/dist/multi-model.browser.js       1.65 kB
                            multi-model/dist/multi-model.browser.d.ts     457 B
./multi-model (edge-light)  multi-model/dist/multi-model.edge-light.js    2.43 kB
                            multi-model/dist/multi-model.edge-light.d.ts  457 B
./multi-model (workerd)     multi-model/dist/multi-model.workerd.js       2.43 kB
                            multi-model/dist/multi-model.workerd.d.ts     457 B

Process finished with exit code 0

It lost ./multi-model (default)

[himself65]

Ok, the reason is I both have ./multi-model directory and ./multi-model.ts file