Lookbehind local keymap setting

[ilan-schemoul]

Problem : #156 we may want a global setting (e.g: lookahead) for most keymaps and then override that setting for one keymap (e.g: lookbehind)
You can now add a local lookbehind/lookahead in the keymap that takes precedence :

      textobjects = {
        select = {
          enable = true,
          lookahead = true,
          keymaps = {
            ["t="] = { query = "@type", desc = "Select right hand side of an assignment", lookbehind = true }, 
          }
        }
      }

[ribru17]

Thank you for the contribution! I think we may have to wait on merging this until #523, due to the nature of the change.

[kiyoon]

The development is now done in main and master is frozen. Can you open a new PR with this feature?

[kiyoon]

I think the name of the args could be lookahead and lookbehind. If they are not defined just use the global. Or I would name it like override_lookahead etc.