update lualine config

the only actual change here is that the filename display will now
include the full path.

however, now a copy of the default `sections` and `inactive_sections`
config have been copied here, just to make it easier to make any
future modifications.

lua/plugins/lualine.lua

@@ -14,6 +14,22 @@ return {
             },
           },
         },
+        sections = {
+          lualine_a = { 'mode' },
+          lualine_b = { 'branch', 'diff', 'diagnostics' },
+          lualine_c = { { 'filename', path = 2 } },
+          lualine_x = { 'encoding', 'fileformat', 'filetype' },
+          lualine_y = { 'progress' },
+          lualine_z = { 'location' },
+        },
+        inactive_sections = {
+          lualine_a = {},
+          lualine_b = {},
+          lualine_c = { 'filename' },
+          lualine_x = { 'location' },
+          lualine_y = {},
+          lualine_z = {},
+        },
         extensions = {
           'lazy',
           'mason',