Further help improvements: Show command aliases in 'hg help something', unless in quiet mode. Show short command description with 'hg help -q something'. Show global options in verbose mode of command help. State that Mercurial is a Distributed SCM.

+ hg init
+ hg add a
+ hg ci -m a -d 0 0
+ hg add b
+ hg diff
diff -r 3903775176ed b
--- /dev/null
+++ b/b
@@ -0,0 +1,1 @@
+123
+ hg diff -r tip
diff -r 3903775176ed b
--- /dev/null
+++ b/b
@@ -0,0 +1,1 @@
+123