UX/UI improvement: enhancing search

[koebel]

From a user perspective, I would expect that search is by default over all categories (title, tags, authors, ... and everything else that is technically possible) unless the user specifies that he/she only wants to search in a certain category. Also content search would be nice.

When the user selects a filter to narrow down the search, it would improve the user experience by

• displaying which filters are currently activated (not only in drop down but in some way that is more visible for the user)
• if there is no blog post that fits the search criteria, make the message clearer by saying something like "Sorry, no results found for "Go" in <search category(s)>"
• allowing a combination of multiple filters
• offer an easy way to reset all filters (something like "remove all filters")
• maybe also resetting filters when using the "reset search" button under the text of the no results message. What might be even better from UX perspective is giving a message to the user that briefly explains that filters have narrowed down the search results and state how many search results there are in total without filters and let the user choose if he/she wants to clear filters or not.
• for the "clear search" button I would expect that it only clears the search terms, not the filters

this example shows some good ways for displaying and removing filters in a intuitive, user friendly way

Originally posted by @koebel in #127 (comment)