Fix various typos (#163)

Found via `codespell -q 3`

Changelog

@@ -14,7 +14,7 @@
 	the necessary line.
 
 2019-09-02:
-  Add support for e2k architectur. Thanks to Michael Shigorin.
+  Add support for e2k architecture. Thanks to Michael Shigorin.
 
 2019-08-01:
   Add min exponent width option in double-to-string conversion.

double-conversion/bignum-dtoa.cc

@@ -276,7 +276,7 @@ static void GenerateShortestDigits(Bignum* numerator, Bignum* denominator,
 
 // Let v = numerator / denominator < 10.
 // Then we generate 'count' digits of d = x.xxxxx... (without the decimal point)
-// from left to right. Once 'count' digits have been produced we decide wether
+// from left to right. Once 'count' digits have been produced we decide whether
 // to round up or down. Remainders of exactly .5 round upwards. Numbers such
 // as 9.999999 propagate a carry all the way, and change the
 // exponent (decimal_point), when rounding upwards.

double-conversion/double-to-string.h

@@ -123,7 +123,7 @@ class DoubleToStringConverter {
   // Example with max_leading_padding_zeroes_in_precision_mode = 6.
   //   ToPrecision(0.0000012345, 2) -> "0.0000012"
   //   ToPrecision(0.00000012345, 2) -> "1.2e-7"
-  // Similarily the converter may add up to
+  // Similarly the converter may add up to
   // max_trailing_padding_zeroes_in_precision_mode in precision mode to avoid
   // returning an exponential representation. A zero added by the
   // EMIT_TRAILING_ZERO_AFTER_POINT flag is counted for this limit.
@@ -181,7 +181,7 @@ class DoubleToStringConverter {
   // Example with decimal_in_shortest_low = -6,
   //              decimal_in_shortest_high = 21,
   //              EMIT_POSITIVE_EXPONENT_SIGN activated, and
-  //              EMIT_TRAILING_DECIMAL_POINT deactived:
+  //              EMIT_TRAILING_DECIMAL_POINT deactivated:
   //   ToShortest(0.000001)  -> "0.000001"
   //   ToShortest(0.0000001) -> "1e-7"
   //   ToShortest(111111111111111111111.0)  -> "111111111111111110000"
@@ -305,7 +305,7 @@ class DoubleToStringConverter {
   // Example with max_leading_padding_zeroes_in_precision_mode = 6.
   //   ToPrecision(0.0000012345, 2) -> "0.0000012"
   //   ToPrecision(0.00000012345, 2) -> "1.2e-7"
-  // Similarily the converter may add up to
+  // Similarly the converter may add up to
   // max_trailing_padding_zeroes_in_precision_mode in precision mode to avoid
   // returning an exponential representation. A zero added by the
   // EMIT_TRAILING_ZERO_AFTER_POINT flag is counted for this limit.

double-conversion/fast-dtoa.cc

@@ -565,15 +565,15 @@ static bool Grisu3(double v,
   // the difference between w and boundary_minus/plus (a power of 2) and to
   // compute scaled_boundary_minus/plus by subtracting/adding from
   // scaled_w. However the code becomes much less readable and the speed
-  // enhancements are not terriffic.
+  // enhancements are not terrific.
   DiyFp scaled_boundary_minus = DiyFp::Times(boundary_minus, ten_mk);
   DiyFp scaled_boundary_plus  = DiyFp::Times(boundary_plus,  ten_mk);
 
   // DigitGen will generate the digits of scaled_w. Therefore we have
   // v == (double) (scaled_w * 10^-mk).
   // Set decimal_exponent == -mk and pass it to DigitGen. If scaled_w is not an
   // integer than it will be updated. For instance if scaled_w == 1.23 then
-  // the buffer will be filled with "123" und the decimal_exponent will be
+  // the buffer will be filled with "123" and the decimal_exponent will be
   // decreased by 2.
   int kappa;
   bool result = DigitGen(scaled_boundary_minus, scaled_w, scaled_boundary_plus,

double-conversion/fixed-dtoa.cc

@@ -395,8 +395,8 @@ bool FastFixedDtoa(double v,
   TrimZeros(buffer, length, decimal_point);
   buffer[*length] = '\0';
   if ((*length) == 0) {
-    // The string is empty and the decimal_point thus has no importance. Mimick
-    // Gay's dtoa and and set it to -fractional_count.
+    // The string is empty and the decimal_point thus has no importance. Mimic
+    // Gay's dtoa and set it to -fractional_count.
     *decimal_point = -fractional_count;
   }
   return true;

double-conversion/string-to-double.h

@@ -86,7 +86,7 @@ class StringToDoubleConverter {
   //      This *must* start with "0x" and separate the exponent with "p".
   //      Examples: 0x1.2p3 == 9.0
   //                0x10.1p0 == 16.0625
-  //      ALLOW_HEX and ALLOW_HEX_FLOATS are indendent.
+  //      ALLOW_HEX and ALLOW_HEX_FLOATS are indented.
   //
   // empty_string_value is returned when an empty string is given as input.
   // If ALLOW_LEADING_SPACES or ALLOW_TRAILING_SPACES are set, then a string

double-conversion/strtod.cc

@@ -550,7 +550,7 @@ float StrtofTrimmed(Vector<const char> trimmed, int exponent) {
   //    low-precision (3 digits):
   //       when read from input: 123
   //       when rounded from high precision: 124.
-  // To do this we simply look at the neigbors of the correct result and see
+  // To do this we simply look at the neighbors of the correct result and see
   // if they would round to the same float. If the guess is not correct we have
   // to look at four values (since two different doubles could be the correct
   // double).