Implicit trivial rules

[cortsf]

To declare simple search engines and quteromarks we need these two trivial rules

[[engine_rules]]
er_template = "engines"
er_alias = "{alias}"
er_url = "{url}"

[[quteromark_rules]]
qr_template = "quteromarks"
qr_alias ="{alias}"
qr_url = "{url}"

Make these rules implicit, allowing to define simple engines and quteromarks (example below) without needing to have such trivial rules explicitly declared in the toml file. This is specially useful for quteromarks since the quteromarks menu is made to work specifically with this rule, which the user has to declare by himself.

[[engines]]
alias = "gh"
url = "https://github.com/search?q={}"

[[quteromarks]]
alias="local"
url="http://127.0.0.1"