Fix various typos, spelling mistakes, and inconsistencies

Change-Id: If8a00ab24285a32840dc9c92697366037554cbca

Documentation/intro-user.txt

diff --git a/Documentation/intro-user.txt b/Documentation/intro-user.txt
index 535248d..9bf6842 100644
--- a/Documentation/intro-user.txt
+++ b/Documentation/intro-user.txt
@@ -591,7 +591,7 @@
 ** `None`:
 +
 For each review label only the voting value is shown. Approvals are
-rendered as a green check mark icon, vetos as a red X icon.
+rendered as a green check mark icon, vetoes as a red X icon.
 +
 ** `Show Name`:
 +