fix typos using misspell (#1374)

pages/common/fzf.md

@@ -10,7 +10,7 @@
 
 `ps axu | fzf`
 
-- Select mutliple files with `Shift + Tab` and write to a file:
+- Select multiple files with `Shift + Tab` and write to a file:
 
 `find {{path/to/search_files}} -type f | fzf -m > {{filename}}`