Fix "precedes" listchar behavior in wrap mode

Previously, the "precedes" character would be rendered on every row
when w_skipcol > 0 (i.e., when viewing a single line longer than the
entire screen), instead of just on the first row. Make sure to only
render it on the first row in this case.

Add a test for this behavior.

Fix documentation for the "precedes" character, which erroneously
stated that it was only active when wrap mode was off.

runtime/doc/options.txt

@@ -3698,9 +3698,8 @@ A jump table for the options with a short description can be found at |Q_op|.
 			off and the line continues beyond the right of the
 			screen.
 							*lcs-precedes*
-	  precedes:c	Character to show in the first column, when 'wrap'
+	  precedes:c	Character to show in the first column, when there is
-			is off and there is text preceding the character
+			text preceding the character visible in the first column.
-			visible in the first column.
 							*lcs-conceal*
 	  conceal:c	Character to show in place of concealed text, when
 			'conceallevel' is set to 1.  A space when omitted.

src/nvim/screen.c

@@ -3763,7 +3763,7 @@ win_line (
      */
     if (lcs_prec_todo != NUL
         && wp->w_p_list
-        && (wp->w_p_wrap ? wp->w_skipcol > 0 : wp->w_leftcol > 0)
+        && (wp->w_p_wrap ? (wp->w_skipcol > 0 && row == 0) : wp->w_leftcol > 0)
         && filler_todo <= 0
         && draw_state > WL_NR
         && c != NUL) {

test/functional/ui/highlight_spec.lua

@@ -657,6 +657,30 @@ describe("'listchars' highlight", function()
     ]])
   end)
 
+  it("'listchar' with wrap", function()
+    screen:set_default_attr_ids({
+      [0] = {bold=true, foreground=Screen.colors.Blue},
+    })
+    feed_command('set wrap')
+    feed_command('set listchars=eol:¬,precedes:< list')
+    feed('90ia<esc>')
+    screen:expect([[
+      {0:<}aaaaaaaaaaaaaaaaaaa|
+      aaaaaaaaaaaaaaaaaaaa|
+      aaaaaaaaaaaaaaaaaaaa|
+      aaaaaaaaa^a{0:¬}         |
+                          |
+    ]])
+    feed('0')
+    screen:expect([[
+      ^aaaaaaaaaaaaaaaaaaaa|
+      aaaaaaaaaaaaaaaaaaaa|
+      aaaaaaaaaaaaaaaaaaaa|
+      aaaaaaaaaaaaaaaaaaaa|
+                          |
+    ]])
+  end)
+
   it("'listchar' in visual mode", function()
     screen:set_default_attr_ids({
       [1] = {background=Screen.colors.Grey90},