patch 9.0.1158: code is indented more than necessary

Problem:    Code is indented more than necessary.
Solution:   Use an early return where it makes sense. (Yegappan Lakshmanan,
            closes #11787)
diff --git a/src/getchar.c b/src/getchar.c
index 3fd518b..2fb9baa 100644
--- a/src/getchar.c
+++ b/src/getchar.c
@@ -259,11 +259,11 @@
     if (buf->bh_curr == NULL)
 	return;  // nothing to delete
     len = (int)STRLEN(buf->bh_curr->b_str);
-    if (len >= slen)
-    {
-	buf->bh_curr->b_str[len - slen] = NUL;
-	buf->bh_space += slen;
-    }
+    if (len < slen)
+	return;
+
+    buf->bh_curr->b_str[len - slen] = NUL;
+    buf->bh_space += slen;
 }
 
 /*
@@ -478,12 +478,12 @@
     void
 ResetRedobuff(void)
 {
-    if (!block_redo)
-    {
-	free_buff(&old_redobuff);
-	old_redobuff = redobuff;
-	redobuff.bh_first.b_next = NULL;
-    }
+    if (block_redo)
+	return;
+
+    free_buff(&old_redobuff);
+    old_redobuff = redobuff;
+    redobuff.bh_first.b_next = NULL;
 }
 
 /*
@@ -493,15 +493,15 @@
     void
 CancelRedo(void)
 {
-    if (!block_redo)
-    {
-	free_buff(&redobuff);
-	redobuff = old_redobuff;
-	old_redobuff.bh_first.b_next = NULL;
-	start_stuff();
-	while (read_readbuffers(TRUE) != NUL)
-	    ;
-    }
+    if (block_redo)
+	return;
+
+    free_buff(&redobuff);
+    redobuff = old_redobuff;
+    old_redobuff.bh_first.b_next = NULL;
+    start_stuff();
+    while (read_readbuffers(TRUE) != NUL)
+	;
 }
 
 /*
@@ -520,11 +520,11 @@
 
     // Make a copy, so that ":normal ." in a function works.
     s = get_buffcont(&save_redo->sr_redobuff, FALSE);
-    if (s != NULL)
-    {
-	add_buff(&redobuff, s, -1L);
-	vim_free(s);
-    }
+    if (s == NULL)
+	return;
+
+    add_buff(&redobuff, s, -1L);
+    vim_free(s);
 }
 
 /*
@@ -944,15 +944,15 @@
     static void
 init_typebuf(void)
 {
-    if (typebuf.tb_buf == NULL)
-    {
-	typebuf.tb_buf = typebuf_init;
-	typebuf.tb_noremap = noremapbuf_init;
-	typebuf.tb_buflen = TYPELEN_INIT;
-	typebuf.tb_len = 0;
-	typebuf.tb_off = MAXMAPLEN + 4;
-	typebuf.tb_change_cnt = 1;
-    }
+    if (typebuf.tb_buf != NULL)
+	return;
+
+    typebuf.tb_buf = typebuf_init;
+    typebuf.tb_noremap = noremapbuf_init;
+    typebuf.tb_buflen = TYPELEN_INIT;
+    typebuf.tb_len = 0;
+    typebuf.tb_off = MAXMAPLEN + 4;
+    typebuf.tb_change_cnt = 1;
 }
 
 /*
@@ -1324,11 +1324,11 @@
     void
 ungetchars(int len)
 {
-    if (reg_recording != 0)
-    {
-	delete_buff_tail(&recordbuff, len);
-	last_recorded_len -= len;
-    }
+    if (reg_recording == 0)
+	return;
+
+    delete_buff_tail(&recordbuff, len);
+    last_recorded_len -= len;
 }
 
 /*
@@ -2230,23 +2230,23 @@
 {
     getchar_common(argvars, rettv);
 
-    if (rettv->v_type == VAR_NUMBER)
-    {
-	char_u		temp[7];   // mbyte-char: 6, NUL: 1
-	varnumber_T	n = rettv->vval.v_number;
-	int		i = 0;
+    if (rettv->v_type != VAR_NUMBER)
+	return;
 
-	if (n != 0)
-	{
-	    if (has_mbyte)
-		i += (*mb_char2bytes)(n, temp + i);
-	    else
-		temp[i++] = n;
-	}
-	temp[i++] = NUL;
-	rettv->v_type = VAR_STRING;
-	rettv->vval.v_string = vim_strsave(temp);
+    char_u		temp[7];   // mbyte-char: 6, NUL: 1
+    varnumber_T	n = rettv->vval.v_number;
+    int		i = 0;
+
+    if (n != 0)
+    {
+	if (has_mbyte)
+	    i += (*mb_char2bytes)(n, temp + i);
+	else
+	    temp[i++] = n;
     }
+    temp[i++] = NUL;
+    rettv->v_type = VAR_STRING;
+    rettv->vval.v_string = vim_strsave(temp);
 }
 
 /*
@@ -4031,10 +4031,10 @@
     void
 reset_last_used_map(mapblock_T *mp)
 {
-    if (last_used_map == mp)
-    {
-	last_used_map = NULL;
-	last_used_sid = -1;
-    }
+    if (last_used_map != mp)
+	return;
+
+    last_used_map = NULL;
+    last_used_sid = -1;
 }
 #endif