Customisable signs' symbols.

doc/gitgutter.txt

@@ -92,7 +92,7 @@ Commands for jumping between marked hunks:
 You can customise:
 
 - The sign column's colours
-- The signs' colours
+- The signs' colours and symbols
 - Line highlights
 - Whether or not vim-gitgutter is on initially (defaults to on)
 - Whether or not line highlighting is on initially (defaults to off)
@@ -128,10 +128,10 @@ like this:
   User-defined (terminal Vim)         highlight SignColumn ctermbg={whatever}
   User-defined (graphical Vim)        highlight SignColumn guibg={whatever}
 
-SIGNS' COLOURS
+SIGNS' COLOURS AND SYMBOLS
 
-To customise these, set up the following highlight groups in your colorscheme
-or |vimrc|:
+To customise the colours, set up the following highlight groups in your
+colorscheme or |vimrc|:
 
 >
   GitGutterAdd          " an added line
@@ -146,6 +146,14 @@ them to existing highlight groups with, say:
   highlight link GitGutterAdd DiffAdd
 <
 
+To customise the symbols, add the following to your |vimrc|:
+>
+  let g:gitgutter_sign_added = 'xx'
+  let g:gitgutter_sign_modified = 'yy'
+  let g:gitgutter_sign_removed = 'zz'
+  let g:gitgutter_sign_modified_removed = 'ww'
+<
+
 LINE HIGHLIGHTS
 
 Similarly to the signs' colours, set up the following highlight groups in your