Optimization: shadow/unshadow only what's needed
Optimization: shadow/unshadow only what's needed

Before:
% time zsh -i -c exit
num  calls                time                       self            name
-----------------------------------------------------------------------------------
 1)  491         126,02     0,26   19,59%     92,08     0,19   14,32%  -zplg-shadow-off
 2)   66          72,82     1,10   11,32%     72,82     1,10   11,32%  -zplg-diff-functions
 3)   36         615,32    17,09   95,67%     68,59     1,91   10,66%  -zplg-load-plugin
 4)  668          62,42     0,09    9,71%     62,42     0,09    9,71%  -zplg-add-report
 5)  491          56,37     0,11    8,76%     56,37     0,11    8,76%  -zplg-shadow-on
 6)   66          51,73     0,78    8,04%     51,73     0,78    8,04%  -zplg-diff-parameter
 7)  262         170,19     0,65   26,46%     46,37     0,18    7,21%  --zplg-shadow-zle
 8)  491          33,94     0,07    5,28%     33,94     0,07    5,28%  -zplg-trim-backup-vars
zsh -i -c exit  1,32s user 0,36s system 98% cpu 1,714 total

After:
% time zsh -i -c exit
num  calls                time                       self            name
-----------------------------------------------------------------------------------
 1)   66          73,18     1,11   14,81%     73,18     1,11   14,81%  -zplg-diff-functions
 2)   36         466,77    12,97   94,46%     72,39     2,01   14,65%  -zplg-load-plugin
 3)  668          60,65     0,09   12,27%     60,65     0,09   12,27%  -zplg-add-report
 4)   66          53,14     0,81   10,75%     53,14     0,81   10,75%  -zplg-diff-parameter
 5)  262          82,27     0,31   16,65%     48,62     0,19    9,84%  --zplg-shadow-zle
 6)  103          39,90     0,39    8,07%     25,55     0,25    5,17%  --zplg-shadow-alias
 7)  458          52,66     0,11   10,66%     24,72     0,05    5,00%  (anon)
 8)   72          23,36     0,32    4,73%     15,72     0,22    3,18%  --zplg-shadow-bindkey
zsh -i -c exit  1,19s user 0,35s system 97% cpu 1,572 total

akatrevorjay/zplugin,psprint/zplugin,psprint/zplugin,psprint/zplugin