lsp: quick fixes for hints and bare library names; comment cleanup

an undefined bare name that a module exports now says which one:
"put_c is used but never defined; did you mean to include rt and use
rt.put_c?", and the import quick fix is titled the same way and marked
preferred when it is the only one, so the editor's auto-fix applies it.

hints gain quick fixes that keep the program's meaning: an unused
parameter, or a local with no other use, is renamed to _; a constant
local with one declarator becomes const; a power-of-two multiply becomes
a parenthesized shift (not when a * / or % binds its left operand); and
let p = rt.new(n) with a small constant becomes let p[n]. the hints no
longer fire for _ discards or for locals already declared const.

whole-line /* */ comments in zc sources are // comments now, and //: is
gone from the maintained sources: the notes it marked were mostly the
documentation of the declaration below, which hovers now show. section
headers are separated from the declarations after them.

1 files changed, 1 insertions, 1 deletions

diff --git a/examples/learn/29-block-comments.zc b/examples/learn/29-block-comments.zc
index a5088eb..9468cc5 100644
--- a/examples/learn/29-block-comments.zc
+++ b/examples/learn/29-block-comments.zc
@@ -1,7 +1,7 @@
 namespace;
 include rt;
 
-/* adds a memory offset to an address. */
+// adds a memory offset to an address.
 int offset_address(int address) {
 	return address + /* offset in memory */ 0x40ff;
 }