Apply suggestion from @lzehl

Co-authored-by: Lyuba Zehl <lyuba.zehl@ebrains.eu>

Author: Alixbonard

schemas/data/rasterImageSequence.shema.tpl.json

@@ -55,7 +55,7 @@
       "_embeddedTypes": [
         "core:QuantitativeValue"
       ],
-      "_instruction": "Enter the physical pixel size for this image (in x,y order).",
+      "_instruction": "Enter the common physical pixel size for the consecutive images (frames) (in x,y order).",
       "maxItems": 2,
       "minItems": 2,
       "type": "array"