docs: update plain text config example (#32)

Author: saecki

README.md

@@ -342,7 +342,7 @@ require('crates').setup {
             loading = " ...",
         },
     },
-    cmp = {
+    src = {
         text = {
             prerelease = " pre-release ",
             yanked = " yanked ",

scripts/README.md.in

@@ -206,7 +206,7 @@ require('crates').setup {
             loading = " ...",
         },
     },
-    cmp = {
+    src = {
         text = {
             prerelease = " pre-release ",
             yanked = " yanked ",