fix!: Don't escape % in progress()/status()

Now the users should escape % in their statusline setting.

Author: tomtomjhj

README.md

@@ -3,6 +3,9 @@
 This is a Neovim plugin/library for generating statusline components from the built-in LSP client.
 
 ## Notices
+- **2022/05/05**: **Breaking change**. `progress()` no longer escapes `%` in the returned string. If
+  you were using `progress()` or `status()` in your `statusline` option, you should wrap the
+  expression inside `%{}` to escape `%`. See [below](#all-together-now) for an example.
 - **2021/03/13**: Some users report success using the Google "Noto Emoji" font for `status_symbol`
   and `indicator_hint`.
 - **2020/11/19**: Please note that the default diagnostics symbols require Font Awesome or a [Nerd
@@ -236,6 +239,12 @@ function! LspStatus() abort
   return ''
 endfunction
 
+" Manually set 'statusline'
+set statusline+=%{LspStatus()}
+
+" ... or use a statusline plugin, e.g. lightline:
+let g:lightline.active.right = [..., ['lsp_status']]
+let g:lightline.component_function = {'lsp_status': 'LspStatus'}
 ```
 
 ## Status

lua/lsp-status/statusline.lua

@@ -47,9 +47,7 @@ local function get_lsp_progress()
       contents = msg.title
       if msg.message then contents = contents .. ' ' .. msg.message end
 
-      -- this percentage format string escapes a percent sign once to show a percentage and one more
-      -- time to prevent errors in vim statusline's because of it's treatment of % chars
-      if msg.percentage then contents = contents .. string.format(" (%.0f%%%%)", msg.percentage) end
+      if msg.percentage then contents = contents .. string.format(" (%.0f%%)", msg.percentage) end
 
       if msg.spinner then
         contents = config.spinner_frames[(msg.spinner % #config.spinner_frames) + 1] .. ' ' ..