spacecheck: check long lines and repeat spaces, fix fallouts

Verify if lines are not longer than 192 characters. Also verify if lines
have less than 79 repeat spaces (and fix one fallout).

To improve readability by avoiding long lines and to prevent adding
overly long lines with text that may go unnoticed in an editor or diff
viewer.

In addition to pre-existing line length limits: 79 for C, 132 for CMake
sources.

Also:
- spacecheck: fix/harden allowlist regexes.
- spacecheck: tidy-up quotes and simplify escaping.
- spacecheck: allow folding strings with repeat spaces.
- GHA: fix a suppressed shellcheck warning.
- GHA/macos: simplify by dropping brew bundle.
- test1119.pl: precompile a regex.
- FAQ.md: delete very long link to a Windows 7/2008 support article
  that's lost it relevance.

Closes #21087

docs/HTTP3.md

@@ -78,7 +78,8 @@ Build ngtcp2:
      % cd ngtcp2
      % autoreconf -fi
      # Change --with-openssl to --with-boringssl for AWS-LC and BoringSSL
-     % ./configure PKG_CONFIG_PATH=/path/to/openssl/lib/pkgconfig:/path/to/nghttp3/lib/pkgconfig LDFLAGS="-Wl,-rpath,/path/to/openssl/lib" --prefix=/path/to/ngtcp2 --enable-lib-only --with-openssl
+     % ./configure PKG_CONFIG_PATH=/path/to/openssl/lib/pkgconfig:/path/to/nghttp3/lib/pkgconfig LDFLAGS="-Wl,-rpath,/path/to/openssl/lib" \
+       --prefix=/path/to/ngtcp2 --enable-lib-only --with-openssl
      % make
      % make install
 
@@ -88,7 +89,8 @@ Build curl (with autotools):
      % git clone https://github.com/curl/curl
      % cd curl
      % autoreconf -fi
-     % ./configure PKG_CONFIG_PATH=/path/to/openssl/lib/pkgconfig LDFLAGS="-Wl,-rpath,/path/to/openssl/lib" --with-openssl=/path/to/openssl --with-ngtcp2=/path/to/ngtcp2 --with-nghttp3=/path/to/nghttp3
+     % ./configure PKG_CONFIG_PATH=/path/to/openssl/lib/pkgconfig LDFLAGS="-Wl,-rpath,/path/to/openssl/lib" \
+       --with-openssl=/path/to/openssl --with-ngtcp2=/path/to/ngtcp2 --with-nghttp3=/path/to/nghttp3
      % make
      % make install
 
@@ -97,7 +99,8 @@ Build curl (with CMake):
      % cd ..
      % git clone https://github.com/curl/curl
      % cd curl
-     % PKG_CONFIG_PATH=/path/to/openssl/lib/pkgconfig:/path/to/ngtcp2/lib/pkgconfig:/path/to/nghttp3/lib/pkgconfig cmake -B bld -DOPENSSL_ROOT_DIR=/path/to/openssl -DUSE_NGTCP2=ON
+     % PKG_CONFIG_PATH=/path/to/openssl/lib/pkgconfig:/path/to/ngtcp2/lib/pkgconfig:/path/to/nghttp3/lib/pkgconfig cmake -B bld \
+       -DOPENSSL_ROOT_DIR=/path/to/openssl -DUSE_NGTCP2=ON
      % cmake --build bld
 
 ## Build with GnuTLS
@@ -128,7 +131,8 @@ Build ngtcp2:
      % git clone -b $NGTCP2_VERSION https://github.com/ngtcp2/ngtcp2
      % cd ngtcp2
      % autoreconf -fi
-     % ./configure PKG_CONFIG_PATH=/path/to/gnutls/lib/pkgconfig:/path/to/nghttp3/lib/pkgconfig LDFLAGS="-Wl,-rpath,/path/to/gnutls/lib" --prefix=/path/to/ngtcp2 --enable-lib-only --with-gnutls
+     % ./configure PKG_CONFIG_PATH=/path/to/gnutls/lib/pkgconfig:/path/to/nghttp3/lib/pkgconfig LDFLAGS="-Wl,-rpath,/path/to/gnutls/lib" \
+       --prefix=/path/to/ngtcp2 --enable-lib-only --with-gnutls
      % make
      % make install
 
@@ -178,7 +182,8 @@ Build ngtcp2:
      % git clone -b $NGTCP2_VERSION https://github.com/ngtcp2/ngtcp2
      % cd ngtcp2
      % autoreconf -fi
-     % ./configure PKG_CONFIG_PATH=/path/to/wolfssl/lib/pkgconfig:/path/to/nghttp3/lib/pkgconfig LDFLAGS="-Wl,-rpath,/path/to/wolfssl/lib" --prefix=/path/to/ngtcp2 --enable-lib-only --with-wolfssl
+     % ./configure PKG_CONFIG_PATH=/path/to/wolfssl/lib/pkgconfig:/path/to/nghttp3/lib/pkgconfig LDFLAGS="-Wl,-rpath,/path/to/wolfssl/lib" \
+       --prefix=/path/to/ngtcp2 --enable-lib-only --with-wolfssl
      % make
      % make install
 
@@ -225,7 +230,8 @@ Build curl:
      % git clone https://github.com/curl/curl
      % cd curl
      % autoreconf -fi
-     % ./configure LDFLAGS="-Wl,-rpath,$PWD/../quiche/target/release" --with-openssl=$PWD/../quiche/quiche/deps/boringssl/src --with-quiche=$PWD/../quiche/target/release
+     % ./configure LDFLAGS="-Wl,-rpath,$PWD/../quiche/target/release" \
+       --with-openssl=$PWD/../quiche/quiche/deps/boringssl/src --with-quiche=$PWD/../quiche/target/release
      % make
      % make install
 
@@ -323,7 +329,9 @@ Get, build and install nghttp2:
      % git clone https://github.com/nghttp2/nghttp2
      % cd nghttp2
      % autoreconf -fi
-     % PKG_CONFIG_PATH=$PKG_CONFIG_PATH:/home/daniel/build-quictls/lib/pkgconfig:/home/daniel/build-nghttp3/lib/pkgconfig:/home/daniel/build-ngtcp2/lib/pkgconfig LDFLAGS=-L/home/daniel/build-quictls/lib CFLAGS=-I/home/daniel/build-quictls/include ./configure --enable-maintainer-mode --prefix=/home/daniel/build-nghttp2 --disable-shared --enable-app --enable-http3 --without-jemalloc --without-libxml2 --without-systemd
+     % PKG_CONFIG_PATH=$PKG_CONFIG_PATH:/path/to/quictls/lib/pkgconfig:/path/to/nghttp3/lib/pkgconfig:/path/to/ngtcp2/lib/pkgconfig \
+       LDFLAGS=-L/path/to/quictls/lib CFLAGS=-I/path/to/quictls/include ./configure --enable-maintainer-mode \
+       --prefix=/path/to/nghttp2 --disable-shared --enable-app --enable-http3 --without-jemalloc --without-libxml2 --without-systemd
      % make && make install
 
 Run the local h3 server on port 9443, make it proxy all traffic through to
@@ -332,7 +340,7 @@ exists in curl's test dir.
 
      % CERT=/path/to/stunnel.pem
      % $HOME/bin/nghttpx $CERT $CERT --backend=localhost,80 \
-      --frontend="localhost,9443;quic"
+       --frontend="localhost,9443;quic"
 
 ### Caddy