Simplify whitespace handling in build/ Jinja templates

Source/build/scripts/templates/InternalRuntimeFlags.idl.tmpl

-{% from "macros.tmpl" import license -%}
+{% from "macros.tmpl" import license %}
 {{ license() }}
 
 [
     WillBeGarbageCollected,
 ] interface InternalRuntimeFlags {
-{%- for feature in features if not feature.custom %}
-{#-
+    {% for feature in features if not feature.custom %}
+{#
     Currently assuming that runtime flags cannot be changed after startup
     it's possible that some can be and should be conditionally readonly.
 #}
-    {% if feature.condition -%} [Conditional={{feature.condition}}] {% endif -%}
+    {%+ if feature.condition %}[Conditional={{feature.condition}}] {% endif -%}
     readonly attribute boolean {{feature.first_lowered_name}}Enabled;
-{%- endfor %}
+    {% endfor %}
 };