feat(previewer): allow passing env to new_termopen_previewer (#3224)

* Allow passing env through term opts

* Add doc update

lua/telescope/previewers/init.lua

@@ -90,13 +90,16 @@ end
 --- Additionally you can define:
 --- - `title` a static title for example "File Preview"
 --- - `dyn_title(self, entry)` a dynamic title function which gets called
+--- - `env` table: define environment variables to forward to the terminal
+---    process. Example:
+---   - `{ ['PAGER'] = '', ['MANWIDTH'] = 50 }`
 --- when config value `dynamic_preview_title = true`
 ---
 --- It's an easy way to get your first previewer going and it integrates well
 --- with `bat` and `less`. Providing out of the box scrolling if the command
 --- uses less.
 ---
---- Furthermore, it will forward all `config.set_env` environment variables to
+--- Furthermore, if `env` is not set, it will forward all `config.set_env` environment variables to
 --- that terminal process.
 previewers.new_termopen_previewer = term_previewer.new_termopen_previewer
 

lua/telescope/previewers/term_previewer.lua

@@ -202,7 +202,7 @@ previewers.new_termopen_previewer = function(opts)
 
       local term_opts = {
         cwd = opts.cwd or vim.loop.cwd(),
-        env = conf.set_env,
+        env = opts.env or conf.set_env,
       }
 
       local cmd = opts.get_command(entry, status)