phpstan: fixes for Varien_Data_Collection

[sreichel]

Description (*)

phpdocs/phpstan fix.

Contribution checklist (*)

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[kiatng]

Do you have plan to fix this:

If the filtering is enabled in the grid, then the collection should have Varien_Data_Collection_Db as parent:

     * @param Varien_Data_Collection|Varien_Data_Collection_Db $collection
     */
    public function getCollection($collection)
    // and: public function setCollection($collection)

[sreichel]

Do you have plan to fix this:

Yes. The "problem" is, that is has no impact on phpstan ... so i dont see it during my tests. Made a new PR. :)

[github-actions]

Unit Test Results

1 files  ±0  1 suites  ±0   0s ⏱️ ±0s
0 tests ±0  0 ✔️ ±0  0 💤 ±0  0 ❌ ±0 
7 runs  ±0  5 ✔️ ±0  2 💤 ±0  0 ❌ ±0 

Results for commit 6081bf1. ± Comparison against base commit e6e5ad7.