tidy-up: miscellaneous

- H3 proxy: re-sync code with original source `curl_ngtcp2.c` to reduce
  differences, and to apply missed minor fixes. Also apply clang-format.
  Drop redundant `#undef`s, casts, `#endif` comments, includes, drop
  intermediate variables, sync include and macro order.
  Follow-up to e78b1b3ecc #21153
- INSTALL-CMAKE.md: move `CURL_ENABLE_SMB` to the enable section.
- tests/http/env: rename `tcpdmp` to `tcpdump` to match object variable.
- mbedtls: drop incorrect `mbedTLS 4+` comments.
  (features are also supported by 3+, meaning it's always supported.)
- lib1648: rename a variable to match purpose.
- CIPHERS.md: alpha-sort link list.
- replace rare `X''` hex markup with `0x`.
- `IP v4/6` -> `IPv4/6`.
- 'version X.Y' -> 'vX.Y', where sensible.
- 'VX.Y' -> 'vX.Y', where sensible.
- fix indents, casing, newlines, typos.

Closes #21772

projects/vms/build_gnv_curl_pcsi_desc.com

@@ -134,7 +134,7 @@ $ write pdsc "   end if;"
 $!
 $write pdsc "   software VMSPORTS ''base' ZLIB ;"
 $write pdsc -
-    "   if (not <software VMSPORTS ''base' ZLIB version minimum V1.2-8>) ;"
+    "   if (not <software VMSPORTS ''base' ZLIB version minimum v1.2-8>) ;"
 $write pdsc "      error NEED_ZLIB;"
 $write pdsc "   end if;"
 $!

projects/vms/build_vms.com

@@ -38,7 +38,7 @@ $!              Always link a debug image.
 $!    NOIEEE    Do not use IEEE floating point.  (Alpha/I64)
 $!              VAX must always use DFLOAT
 $!    NOLARGE   Disable large-file support if large file support available.
-$!              (Non-VAX, VMS >= V7.2.)
+$!              (Non-VAX, VMS >= v7.2.)
 $!    NOLDAP    Disable LDAP support if LDAP is available.
 $!    NOKERBEROS   Disable Kerberos support if Kerberos is available.
 $!    LIST      Create C compiler listings and linker maps.

projects/vms/curl_gnv_build_steps.txt

@@ -20,7 +20,7 @@ Currently building curl using GNV takes longer than building curl via DCL.
 The GNV procedure actually uses the same configure and makefiles that
 Unix builds use.
 
-Building curl on OpenVMS using GNV requires GNV V2.1-2 or the updated
+Building curl on OpenVMS using GNV requires GNV v2.1-2 or the updated
 images that are available via anonymous FTP at encompasserve.org in the gnv
 directory.  It also requires the GNV Bash 4.2.45 kit as an update from the
 same location or from the sourceforge.net GNV project.

projects/vms/readme

@@ -19,9 +19,9 @@ curl_gnv_build_steps.txt and other useful information.
 
 Prerequisites:
 
-OpenVMS V7.0 or later (any platform)
-DECC V6.5 or later
-OpenSSL or hp SSL, if you want SSL support
+OpenVMS v7.0 or later (any platform)
+DECC v6.5 or later
+OpenSSL or HP SSL, if you want SSL support
 
 What is Here: