Auto-populate known URLs when specifying thread’s path

[corywatilo]

Squeak! lets you specify which page(s) a question appears on.

Rather than manually typing URLs Squeak! already knows about (like when Squeak! detects a pageload on a new page), we should auto-suggest these URLs so users don't have to repeatedly type them out. (In the screenshot below, you can see Chrome auto-suggesting based on previous URLs, but we should do this by querying all URLs and auto-suggesting them without browser-specific autofill.)

[shyblackcat]

Make input field become select or autocomplete input by querying all paths and filter by the keyword user entering