feat(completion): Add binding to force completion

Add a binding for `<C-f>` to force completion.
This allows for completions to be started at the start of a line or where
there isn't any context to complete from

This is useful when you want to browse the possible completions without
knowing what you're looking for

lua/plugins/spec/completion.lua

@@ -92,6 +92,9 @@ return {
 							select = false,
 						}),
 					}),
+					["<C-F>"] = cmp.mapping(function(fallback)
+						cmp.complete()
+					end),
 				},
 				sources = cmp.config.sources({
 					{ name = "lazydev" },