Remove 4,000-character limit note for Copilot code review custom instructions (#61721)

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: ria-gopu <189655821+ria-gopu@users.noreply.github.com>
Co-authored-by: Joe Clark <31087804+jc-clark@users.noreply.github.com>

Author: 3 people

data/reusables/copilot/code-review/custom-instructions-limit.md

@@ -1,3 +1,2 @@
 > [!NOTE]
-> * {% data variables.copilot.copilot_code-review_short %} only reads the first 4,000 characters of any custom instruction file. Any instructions beyond this limit will not affect the reviews generated by {% data variables.copilot.copilot_code-review_short %}. This limit does not apply to {% data variables.copilot.copilot_chat_short %} or {% data variables.copilot.copilot_cloud_agent %}.
-> * {% data reusables.copilot.code-review.custom-instructions-branch %}
+> {% data reusables.copilot.code-review.custom-instructions-branch %}