docs(functions): merge manual-only examples and notes into headers

Folds the examples Section 5 carried but the headers did not into each
function's `# EXAMPLE`, and moves the three lines that only looked like
examples -- the two typo-abbreviation notes and rm's /usr/bin/rm fallback --
into `# NOTES`, the label already in use.

Also corrects gi's synopsis, which omitted -l, and documents yt-dlp's
--no-embed-thumbnail in `# ARGUMENTS`.

functions/gi.fish

@@ -5,7 +5,7 @@
 #   04-git-and-version-control
 #
 # SYNOPSIS
-#   gi [-h] [-b] [-p] [-s] [targets...]
+#   gi [-h] [-b] [-p] [-s] [-l] [targets...]
 #
 # DESCRIPTION
 #   Generates .gitignore content by querying the gitignore.io API. Appends
@@ -27,6 +27,8 @@
 #
 # EXAMPLE
 #   gi python,venv
+#   gi -b -p
+#   gi -s node > .gitignore
 function gi --description 'Generate .gitignore files using the gitignore.io API'
     argparse h/help d/description l/list b/boilerplate p/prompt s/stdout -- $argv
     or return 1