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/logs.fish

@@ -21,6 +21,8 @@
 #
 # EXAMPLE
 #   logs -c paru
+#   logs
+#   logs -c scrollback
 function logs --description 'Browse terminal log files interactively with fzf'
     # Opinionated guard (C4): integrations disabled
     if not __fish_config_op_enabled __fish_config_op_integrations