Merge pull request #2298 from RazvanN7/Fix_structdd

Fix quotations in struct.dd
merged-on-behalf-of: Sebastian Wilzbach <sebi.wilzbach@gmail.com>

Author: dlang-bot

spec/struct.dd

@@ -783,7 +783,7 @@ void main()
         $(P An unqualified postblit will get called even if the
         struct is instantiated as `immutable` or `const`, but
         the compiler issues an error if the struct is instantiated
-        as shared:)
+        as `shared`:)
 
 $(SPEC_RUNNABLE_EXAMPLE_COMPILE
 ---
@@ -824,8 +824,8 @@ void main()
         $(P Note that when `const` and `immutable` are used to explicitly
         qualify a postblit as in `this(this) const immutable;` or
         `const immutable this(this);` - the order in which the qualifiers
-        are declared does not matter - the compiler generates a `conflicting
-        attribute error`, however declaring the struct as `const`/`immutable`
+        are declared does not matter - the compiler generates a conflicting
+        attribute error, however declaring the struct as `const`/`immutable`
         and the postblit as `immutable`/`const` achieves the effect of applying
         both qualifiers to the postblit. In both cases the postblit is
         qualified with the more restrictive qualifier, which is `immutable`.