Fix width of commit message to fit 72 chars

Apparently there are some rounding errors affecting the width
calculation. Even adding 0.03px width would have been sufficient to fit
the 72 chars. Weird.

Change-Id: I1db0fc203c93195cf07a09d7bd499f79b9506945
diff --git a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.html b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.html
index 471560d..90d9997 100644
--- a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.html
+++ b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.html
@@ -135,15 +135,15 @@
         line-height: var(--line-height-mono);
         margin-right: var(--spacing-l);
         margin-bottom: var(--spacing-l);
-        /* Account for border and padding */
-        max-width: calc(72ch + 2px + 2*var(--spacing-m));
+        /* Account for border and padding and rounding errors. */
+        max-width: calc(72ch + 2px + 2*var(--spacing-m) + 0.4px);
       }
       .commitMessage gr-linked-text {
         word-break: break-word;
       }
       #commitMessageEditor {
-        /* Account for border and padding */
-        min-width: calc(72ch + 2px + 2*var(--spacing-m));
+        /* Account for border and padding and rounding errors. */
+        min-width: calc(72ch + 2px + 2*var(--spacing-m) + 0.4px);
       }
       .editCommitMessage {
         margin-top: var(--spacing-l);