help: add pad function to template help
Commit aa51392da507 introduced a pad function for use in templates, but did
not add the corresponding documentation to 'hg help templating'.
--- a/mercurial/help/templates.txt Fri Aug 15 03:24:40 2014 +0200
+++ b/mercurial/help/templates.txt Mon Aug 25 15:10:09 2014 +0200
@@ -57,6 +57,8 @@
- label(label, expr)
+- pad(text, width[, fillchar, right])
+
- revset(query[, formatargs])
- rstdoc(text, style)