Small improvements.

[Raimondi]

• funced and fish_indent always uses tabs for indentation, use fish#Indent() to fix it. Works better with the improved fish#Indent().
• ftdetect should contain filetype detection code. Move autocmds to plugin/fish.vim.
• Match new funced temp file name.
• Add "else", "else if" and "case" to b:match_words to follow what's used by Vim's ftplugins.
• Use "syn sync fromstart" for a more accurate highlighting.

[chemzqm]

:+1: