zsh: switch to zinit & zsh-fsh

These are significantly faster to load, and are actively maintained.
Functionality is almost identical from a usability perspective.
The primary motivation for this change is the several orders of
magnitude faster shell loading times, which should help with
productivity on overloaded and underpowered hardware.

Signed-off-by: Joe Groocock <me@frebib.net>

fsh/fish.ini

@@ -0,0 +1,82 @@
+[base]
+default          = 12
+unknown-token    = red,bold
+commandseparator = cyan
+redirection      = cyan,bold
+here-string-tri  = yellow
+here-string-text = 18
+here-string-var  = cyan,bg:18
+exec-descriptor  = yellow,bold
+comment          = 7
+correct-subtle   = 12
+incorrect-subtle = red
+subtle-separator = green
+subtle-bg        = bg:18
+secondary        =
+recursive-base   =
+
+[command-point]
+reserved-word  = yellow
+subcommand     = yellow
+alias          = blue
+suffix-alias   = green
+global-alias   = blue,bold
+builtin        = blue
+function       = blue
+command        = blue
+precommand     = blue
+hashed-command = green
+single-sq-bracket = green
+double-sq-bracket = green
+double-paren   = yellow
+
+[paths]
+path          = cyan
+pathseparator = cyan
+path-to-dir   = magenta,underline
+globbing      = red
+globbing-ext  = 13
+
+[brackets]
+paired-bracket = bg:blue
+bracket-level-1 = green,bold
+bracket-level-2 = yellow,bold
+bracket-level-3 = cyan,bold
+
+[arguments]
+single-hyphen-option   = 12
+double-hyphen-option   = 12
+back-quoted-argument   = none
+single-quoted-argument = yellow
+double-quoted-argument = yellow
+dollar-quoted-argument = yellow
+
+[in-string]
+; backslash in $'...'
+back-dollar-quoted-argument           = cyan
+; backslash or $... in "..."
+back-or-dollar-double-quoted-argument = cyan
+
+[other]
+variable             = 113
+assign               = green
+assign-array-bracket = green
+history-expansion    = blue,bold
+
+[math]
+mathvar = blue,bold
+mathnum = magenta
+matherr = red
+
+[for-loop]
+forvar = none
+fornum = magenta
+; operator
+foroper = yellow
+; separator
+forsep = yellow,bold
+
+[case]
+case-input       = green
+case-parentheses = yellow
+case-condition   = bg:blue