ci: rename is-pre-merge-for-marge to is-merge-attempt to be clearer

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/26451>

.gitlab-ci.yml

@@ -26,7 +26,7 @@ workflow:
     - if: $CI_COMMIT_BRANCH && $CI_OPEN_MERGE_REQUESTS && $CI_PIPELINE_SOURCE == "push"
       when: never
     # merge pipeline
-    - if: &is-pre-merge-for-marge $GITLAB_USER_LOGIN == "marge-bot" && $CI_PIPELINE_SOURCE == "merge_request_event"
+    - if: &is-merge-attempt $GITLAB_USER_LOGIN == "marge-bot" && $CI_PIPELINE_SOURCE == "merge_request_event"
       variables:
         KERNEL_IMAGE_BASE: https://${S3_HOST}/mesa-lava/${KERNEL_REPO}/${KERNEL_TAG}
         MESA_CI_PERFORMANCE_ENABLED: 1
@@ -213,7 +213,7 @@ include:
       when: on_success
     # Run pipeline by default if it was triggered by Marge Bot, is for a
     # merge request, and any files affecting the pipeline were changed
-    - if: *is-pre-merge-for-marge
+    - if: *is-merge-attempt
       changes:
         *all_paths
       when: on_success
@@ -225,7 +225,7 @@ include:
       when: on_success
     # Just skip everything for MRs which don't actually change anything in the
     # build - the same rules as above, but without the file-change rules
-    - if: *is-pre-merge-for-marge
+    - if: *is-merge-attempt
       when: never
     - if: *is-post-merge
       when: never