docs: rework of chapter "Install with apache"

BTW: normalize installation-nginx.rst

utils/lib.sh

@@ -634,9 +634,15 @@ if [[ -z "${APACHE_SITES_AVAILABE}" ]]; then
 fi
 
 apache_is_installed() {
-    (command -v apachectl \
-        && command -v a2ensite \
-        && command -v a2dissite ) &>/dev/null
+    case $DIST_ID-$DIST_VERS in
+        ubuntu-*|debian-*)
+            (command -v apachectl \
+                 && command -v a2ensite \
+                 && command -v a2dissite ) &>/dev/null
+            ;;
+        arch) (command -v httpd) ;;
+        fedora) (command -v httpd) ;;
+    esac
 }
 
 apache_reload() {

utils/searx.sh

@@ -735,6 +735,11 @@ This installs the searx uwsgi app as apache site.  If your server is public to
 the internet, you should instead use a reverse proxy (filtron) to block
 excessively bot queries."
 
+    case $DIST_ID-$DIST_VERS in
+        ubuntu-*|debian-*) : ;;
+        *) err_msg "sorry distro $DIST_ID $DIST_VERS not yet supported"; exit 42 ;;
+    esac
+
     ! apache_is_installed && err_msg "Apache is not installed."
 
     if ! ask_yn "Do you really want to install apache site for searx-uwsgi?"; then

utils/templates/etc/apache2/sites-available/morty.conf

@@ -18,8 +18,8 @@ ProxyPreserveHost On
     ProxyPass http://${MORTY_LISTEN}
     RequestHeader set X-Script-Name ${PUBLIC_URL_PATH_MORTY}
 
-    # In Apache it seems, that setting HTTP_HOST header direct here does have no
-    # effect.  I needed to set 'ProxyPreserveHost On' (see above).
+    # In Apache it seems, that setting HTTP_HOST header directive here does have
+    # no effect.  I needed to set 'ProxyPreserveHost On' (see above).
 
     # RequestHeader set Host ${PUBLIC_HOST}
 

utils/templates/etc/apache2/sites-available/searx.conf:filtron

@@ -23,8 +23,8 @@ ProxyPreserveHost On
     ProxyPass http://${FILTRON_LISTEN}
     RequestHeader set X-Script-Name ${FILTRON_URL_PATH}
 
-    # In Apache it seems, that setting HTTP_HOST header direct here does have no
-    # effect.  I needed to set 'ProxyPreserveHost On' (see above).  HTTP_HOST
+    # In Apache it seems, that setting HTTP_HOST header directive here does have
+    # no effect.  I needed to set 'ProxyPreserveHost On' (see above).  HTTP_HOST
     # (ProxyPreserveHost On) is needed by searx to render correct *Search URL*
     # in the *Link* box and *saved preference*.