BUG: Fix execution time writing (#451)
BUG: Fix execution time writing (#451)

Tiny bugfix for names that can end in underscores like `my_example_.py`, which can cause RST parsing problems. Fix it by rendering it as code (which looks better anyway IMO).

@drammock can you see if this fixes your problem with names that end in underscores in MNE?
Eric89GXL/sphinx-gallery,lesteve/sphinx-gallery,sphinx-gallery/sphinx-gallery,Titan-C/sphinx-gallery,lesteve/sphinx-gallery,sphinx-gallery/sphinx-gallery,Eric89GXL/sphinx-gallery,Titan-C/sphinx-gallery