ci(doc-linter): delete lint_mac dead code

`lint_mac()` was called and its return value immediately overwritten
with `None`:

    err_mac = lint_mac(cnt, line.strip())
    # disable mac detection for the moment, too many false positives
    err_mac = None

The comment is correct — MAC linting produced too many false
positives — but the cleanup never landed. The dead call ran on every
line for every linted file, and the function/MAC-regex/MAC-error-text
all sat in the source as a misleading hint that MAC linting was a
live feature.

Delete:
- the `MAC` regex constant
- the `lint_mac()` function
- the `err_mac = lint_mac(...)`, `err_mac = None`, and the `err_mac`
  entry in the tuple iterated by the error-collection loop in
  `handle_file_action()`

Tracked as item 9 of the rolling-side cleanup backlog flagged across
the PR #2014 / #2019 / #2020 reviews. When MAC linting is genuinely
wanted again, recover the regex/function from git history and wire it
in cleanly.

🤖 Generated by [robots](https://vyos.io)

(cherry picked from commit ac9f61e5ae366774e51975b0faddd7ba07996762)

1 files changed, 1 insertions, 19 deletions

diff --git a/scripts/doc-linter.py b/scripts/doc-linter.py
index 8e74600f..790409de 100644
--- a/scripts/doc-linter.py
+++ b/scripts/doc-linter.py
@@ -23,10 +23,6 @@ IPV6GROUPS = (
 )
 IPV6ADDR = '|'.join(['(?:{})'.format(g) for g in IPV6GROUPS[::-1]])  # Reverse rows for greedy match
 
-MAC = r'([0-9A-F]{2}[:-]){5}([0-9A-F]{2})'
-
-NUMBER = r"([\s']\d+[\s'])"
-
 SUPPORTED_EXTS = ('.md', '.rst', '.txt')
 
 # Linter only applies to published documentation sources under docs/. Repo-root
@@ -92,17 +88,6 @@ def is_suppression_marker(line, kind, in_md_fence, in_rst_codeblock,
     return False
 
 
-def lint_mac(cnt, line):
-    """Flag MAC addresses outside the RFC 7042 documentation range."""
-    mac = re.search(MAC, line, re.I)
-    if mac is not None:
-        mac = mac.group()
-        u_mac = re.search(r'((00)[:-](53)([:-][0-9A-F]{2}){4})', mac, re.I)
-        m_mac = re.search(r'((90)[:-](10)([:-][0-9A-F]{2}){4})', mac, re.I)
-        if u_mac is None and m_mac is None:
-            return (f"Use MAC reserved for Documentation (RFC7042): {mac}", cnt, 'error')
-
-
 def lint_ipv4(cnt, line):
     """Flag IPv4 addresses outside RFC 5737 / private / multicast ranges."""
     ip = re.search(IPV4ADDR, line, re.I)
@@ -222,13 +207,10 @@ def handle_file_action(filepath):
 
             test_line_length = not (in_md_fence or in_rst_codeblock)
 
-            err_mac = lint_mac(cnt, line.strip())
-            # disable mac detection for the moment, too many false positives
-            err_mac = None
             err_ip4 = lint_ipv4(cnt, line.strip())
             err_ip6 = lint_ipv6(cnt, line.strip())
             err_len = lint_linelen(cnt, line) if test_line_length else None
-            for e in (err_mac, err_ip4, err_ip6, err_len):
+            for e in (err_ip4, err_ip6, err_len):
                 if e:
                     errors.append(e)