Search doesn't work for topics with one symbol or with only special symbols in title

Scenario #1

Preconditions:
Create several topics with one symbol in a title (for ex. 'a' put in a title, 'aa' put in a content)

Steps to reproduce:

1. Go to jcommune and enter search query with 'a'

Actual result:
No results found

Expected result:
Search results should display topics created in precondition

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Scenario #2

Preconditions:
Create several topics with only special symbols symbols in a title and in a content (for ex. '~!@#$%^&*()_+{}|:"<>?[]\;',./`' put in a title and in a content)

Steps to reproduce:

1. Go to jcommune and enter search query with '~!@#$%^&*()_+{}|:"<>?[]\;',./`'

Actual result:
No results found

Expected result:
Search results should display topics created in precondition