Remove incorrect doc comment about constraint argument.
Remove incorrect doc comment about constraint argument.

This overload of drawImageRect() does not take a `constraint` argument.
The comment about constraints appears to have been mistakenly copy-
pasted from the overload above this one.

Change-Id: If0253eec5f21f73b1dffb4dbcd7567aa37e82320
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/291200
Auto-Submit: John Stiles <f4fcf42d3bb5924557f1eeb3be66747535e585da@google.com>
Reviewed-by: Mike Klein <14574f09dfa9b4e14759b88c3426a495a0e627b0@google.com>
Commit-Queue: Mike Klein <14574f09dfa9b4e14759b88c3426a495a0e627b0@google.com>

google/skia,aosp-mirror/platform_external_skia,google/skia,google/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,google/skia,google/skia,aosp-mirror/platform_external_skia,google/skia,aosp-mirror/platform_external_skia,google/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,google/skia,aosp-mirror/platform_external_skia,google/skia,google/skia,aosp-mirror/platform_external_skia