Expect ns regexp to be at the start of a line

Otherwise, having some code like

    (defmacro with-ns [ns & body]
      `(let [old-ns# (ns-name *ns*)]
         (in-ns ~ns)
         ~@Body
         (finally
           (in-ns old-ns#))))

would trip clojure-mode into thinking there are two namespaces there,
even though there are none.

Author: Malabarba

clojure-mode.el

@@ -1216,7 +1216,6 @@ nil."
 
 (defconst clojure-namespace-name-regex
   (rx line-start
-      (zero-or-more whitespace)
       "("
       (zero-or-one (group (regexp "clojure.core/")))
       (zero-or-one (submatch "in-"))