Export of internal Abseil changes

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1829e203300191671abd4b478ca189019e6f88b1 by Abseil Team <absl-team@google.com>:

Don't return true from Demangle() when we didn't actually produce demangled output.

PiperOrigin-RevId: 332544020

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239b617bd8322cfda69d0dcdd3d78499ed61206d by Abseil Team <absl-team@google.com>:

Minor documentation fix.

PiperOrigin-RevId: 332517877

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d566c156619bbdceaf6e84bd0d3aa575d5e790f8 by Gennadiy Rozental <rogeeff@google.com>:

Added missing asserts for seq.index() < capacity_ and unified their usage based on has_element().

Import of https://github.com/abseil/abseil-cpp/pull/781

PiperOrigin-RevId: 332229369
GitOrigin-RevId: 1829e203300191671abd4b478ca189019e6f88b1
Change-Id: I5bb1f713497fef54a7abaf2020be91cb32e87b93

absl/container/internal/raw_hash_set.h

@@ -1327,6 +1327,7 @@ class raw_hash_set {
       }
       if (ABSL_PREDICT_TRUE(g.MatchEmpty())) return end();
       seq.next();
+      assert(seq.index() < capacity_ && "full table!");
     }
   }
   template <class K = key_type>
@@ -1678,8 +1679,8 @@ class raw_hash_set {
 #endif
         return {seq.offset(mask.LowestBitSet()), seq.index()};
       }
-      assert(seq.index() < capacity_ && "full table!");
       seq.next();
+      assert(seq.index() < capacity_ && "full table!");
     }
   }
 
@@ -1710,6 +1711,7 @@ class raw_hash_set {
       }
       if (ABSL_PREDICT_TRUE(g.MatchEmpty())) break;
       seq.next();
+      assert(seq.index() < capacity_ && "full table!");
     }
     return {prepare_insert(hash), true};
   }

absl/debugging/internal/demangle.cc

@@ -1936,7 +1936,8 @@ static bool Overflowed(const State *state) {
 bool Demangle(const char *mangled, char *out, int out_size) {
   State state;
   InitState(&state, mangled, out, out_size);
-  return ParseTopLevelMangledName(&state) && !Overflowed(&state);
+  return ParseTopLevelMangledName(&state) && !Overflowed(&state) &&
+         state.parse_state.out_cur_idx > 0;
 }
 
 }  // namespace debugging_internal

absl/status/status.h

@@ -365,8 +365,8 @@ class ABSL_MUST_USE_RESULT Status final {
   // Constructors
 
   // This default constructor creates an OK status with no message or payload.
-  // Avoid this constructor and pefer explicit construction of an OK status with
-  // `absl::OkStatus()`.
+  // Avoid this constructor and prefer explicit construction of an OK status
+  // with `absl::OkStatus()`.
   Status();
 
   // Creates a status in the canonical error space with the specified