src/sage/rings/padics/padic_template_element.pxi: add "needs sage.libs.eclib"

One example in this file requires "needs sage.libs.eclib" to pass
when eclib is not installed (or is disabled).

Author: orlitzky

src/sage/rings/padics/padic_template_element.pxi

@@ -537,7 +537,7 @@ cdef class pAdicTemplateElement(pAdicGenericElement):
 
         Check to see that :issue:`10292` is resolved::
 
-            sage: # needs sage.schemes
+            sage: # needs sage.schemes sage.libs.eclib
             sage: E = EllipticCurve('37a')
             sage: R = E.padic_regulator(7)
             sage: len(R.expansion())