Rationalize $LESS uses

Stop using "--no-init"/"-X" because we have no actual reason to and it
may break mouse initialization on my best friend macOS.

Use --RAW-CONTROL-CHARS, the capital version that only lets through
specific escape sequences, not *everything* - we shouldn't have
anything weird here, but less heavily discourages the other version.

Allow a user's $LESS to override.

Fixes #7997.

share/functions/__fish_print_help.fish

@@ -119,13 +119,13 @@ function __fish_print_help --description "Print help message for the specified f
             not isatty stdout
             and set pager cat # cannot use a builtin here
             # similar to man, but add -F to quit paging when the help output is brief (#6227)
-            set -xl LESS isrFX
+            not set -qx LESS
+            and set -xl LESS isRF
             # less options:
             # -i (--ignore-case) search case-insensitively, like man
             # -s (--squeeze-blank-lines) not strictly necessary since we already do that above
-            # -r (--raw-control-chars) to display bold, underline and colors
+            # -R (--RAW-CONTROL-CHARS) to display colors and such
             # -F (--quit-if-one-screen) to maintain the non-paging behavior for small outputs
-            # -X (--no-init) not sure if this is needed but git uses it
             $pager
         end
 end

share/functions/history.fish

@@ -93,7 +93,7 @@ function history --description "display or manipulate interactive command histor
                 # screen from clearing on quit, so there is something to see if it exits.
                 # These are two of the options `git` sets through $LESS before starting the pager.
                 not set -qx LESS
-                and set -x LESS --quit-if-one-screen --no-init
+                and set -x LESS --quit-if-one-screen
                 not set -qx LV # ask the pager lv not to strip colors
                 and set -x LV -c