templater: make pad function evaluate both string and rawstring templates

"pad" function and "rawstring" type were introduced in parallel, aa51392da507
in default and 5ab28a2e9962 in stable respectively. Therefore, "pad" function
lacked handling of "rawstring" unintentionally.

mercurial/templater.py

@@ -310,10 +310,7 def pad(context, mapping, args):
 
     width = int(args[1][1])
 
-    text = stringify(args[0][0](context, mapping, args[0][1]))
-    if args[0][0] == runstring:
-        text = stringify(runtemplate(context, mapping,
-            compiletemplate(text, context)))
+    text = stringify(_evalifliteral(args[0], context, mapping))
 
     right = False
     fillchar = ' '

tests/test-command-template.t

@@ -3042,6 +3042,14 Test pad function
   1------------------- {node|short}
   0------------------- test
 
+Test template string in pad function
+
+  $ hg log -r 0 -T '{pad("\{{rev}}", 10)} {author|user}\n'
+  {0}        test
+
+  $ hg log -r 0 -T '{pad(r"\{rev}", 10)} {author|user}\n'
+  \0         test
+
 Test ifcontains function
 
   $ hg log --template '{rev} {ifcontains(rev, "2 two 0", "is in the string", "is not")}\n'