change CodeReview-n default labels (again)

commit 2474e52be made them less easily misunderstood, but also changed
the verb from "submit" to "merge", which is counter to much of our
terminology, and the default of the change.submitLabel option. this
commit rectifies that, and also converts some instances of the original
strings which were missed in the previous change (or have crept back in
since).

Release-Notes: skip
Change-Id: I2f9b1b9c443abf5e8dafcfa9adc71c99d2a22fa0
diff --git a/Documentation/intro-gerrit-walkthrough.txt b/Documentation/intro-gerrit-walkthrough.txt
index 6565ba4..ff37ffc 100644
--- a/Documentation/intro-gerrit-walkthrough.txt
+++ b/Documentation/intro-gerrit-walkthrough.txt
@@ -161,8 +161,8 @@
 * `+2 Looks good to me, approved`
 * `+1 Looks good to me, but someone else must approve`
 * `0 No score`
-* `-1 I would prefer that you didn't submit this`
-* `-2 Do not submit`
+* `-1 I would prefer this is not submitted as is`
+* `-2 This shall not be submitted`
 
 In addition, a change must have at least one `+2` vote and no `-2` votes before
 it can be submitted. These numerical values do not accumulate. Two