docs(functions): standardize all function doc blocks to UNIX man-page style

Replace all ad-hoc inline comments between license headers and function
declarations with consistent SYNOPSIS / DESCRIPTION / ARGUMENTS / RETURNS /
EXAMPLE blocks across all 99 project-owned functions/ files. No executable
logic, variable names, or exit codes were modified.

Completes Task #6 from AGENTS.md (Retroactive Function Documentation
Standardization).

functions/less.fish

@@ -1,6 +1,18 @@
 # Copyright (C) 2026 Rootiest
 # SPDX-License-Identifier: AGPL-3.0-or-later
 
+# SYNOPSIS
+#   less [args...]
+#
+# DESCRIPTION
+#   Pager wrapper that tries $PAGER, then ov, then less, then more, then cat
+#   as fallbacks in that order.
+#
+# ARGUMENTS
+#   args...  Files or options forwarded to the pager
+#
+# EXAMPLE
+#   less /var/log/syslog
 function less --wraps='ov' --description 'Pager wrapper: $PAGER → ov → less → more → cat'
     if set -q PAGER; and command -q $PAGER
         command $PAGER $argv