Merge client's and global auto_complete_selector

[rchl]

When client specifies auto_complete_selector then it looks like currently it completely replaces the global auto_complete_selector:

LSP/plugin/session_view.py

Lines 210 to 220 in c7d622c

	"""This method actually modifies the auto_complete_triggers entries for the view."""
	selector = self.session.config.auto_complete_selector
	if not selector:
	# If the user did not set up an auto_complete_selector for this server configuration, fallback to the
	# "global" auto_complete_selector of the view.
	selector = str(settings.get("auto_complete_selector"))
	trigger = {
	"selector": selector,
	# This key is not used by Sublime, but is used as a "breadcrumb" to figure out what needs to be removed
	# from the auto_complete_triggers array once the session is stopped.
	"server": self.session.config.name

Shouldn't there be a way to merge specified selector with the global one?

There are pros and cons of merging but I think it would make sense for the client to only care about special cases and still allow the global selectors to apply.

The example that made me file this is: I want to make LSP-typescript / LSP-vue provide completions within import paths (scope something like meta.import meta.string) but if I do that then now I also have to repeat global selectors and then the user potentially also has to override that setting manually to consider he's customizations to auto_complete_selector.

Implementation wise, the setting could optionally take an object with selector and strategy properties where stategy could be either replace or merge.