too-many-lines: make lint adhere to lint message convention

clippy_lints/src/functions.rs

@@ -374,7 +374,7 @@ impl<'tcx> Functions {
         }
 
         if line_count > self.max_lines {
-            span_lint(cx, TOO_MANY_LINES, span, "This function has a large number of lines.")
+            span_lint(cx, TOO_MANY_LINES, span, "this function has a large number of lines")
         }
     }
 

tests/ui-toml/functions_maxlines/test.stderr

@@ -1,4 +1,4 @@
-error: This function has a large number of lines.
+error: this function has a large number of lines
   --> $DIR/test.rs:18:1
    |
 LL | / fn too_many_lines() {
@@ -9,7 +9,7 @@ LL | | }
    |
    = note: `-D clippy::too-many-lines` implied by `-D warnings`
 
-error: This function has a large number of lines.
+error: this function has a large number of lines
   --> $DIR/test.rs:38:1
    |
 LL | / fn comment_before_code() {

tests/ui/functions_maxlines.stderr

@@ -1,4 +1,4 @@
-error: This function has a large number of lines.
+error: this function has a large number of lines
   --> $DIR/functions_maxlines.rs:58:1
    |
 LL | / fn bad_lines() {