Fix minor grammar issue in 'from-vim' docs (#6667)

book/src/from-vim.md

@@ -2,9 +2,9 @@
 
 Helix's editing model is strongly inspired from Vim and Kakoune, and a notable
 difference from Vim (and the most striking similarity to Kakoune) is that Helix
-follows the `selection → action` model. This means that the whatever you are
+follows the `selection → action` model. This means that whatever you are
-going to act on (a word, a paragraph, a line, etc) is selected first and the
+going to act on (a word, a paragraph, a line, etc.) is selected first and the
-action itself (delete, change, yank, etc) comes second. A cursor is simply a
+action itself (delete, change, yank, etc.) comes second. A cursor is simply a
 single width selection.
 
 See also Kakoune's [Migrating from Vim](https://github.com/mawww/kakoune/wiki/Migrating-from-Vim) and Helix's [Migrating from Vim](https://github.com/helix-editor/helix/wiki/Migrating-from-Vim).