Post template: return string instead of setting then return

[niallkennedy]

In post template if a password is required to access the post a variable is currently set and the variable returned in the next line.

Return the result of get_the_password_form() instead of writing to a variable and immediately returning that variable.

return result of password form

I wouldn't really call it "performance" but it is indeed good practice to not create a variable you only use once.

In [19812]:

Don't create a variable we only use once. props niallkennedy, fixes #19941.