Fix typos in api.md

Fix typos in api.md

* 2.x: (43 commits)
  Bump versions for dev.
  Update maintenance docs.
  Revert accidental changes to mocha.js.
  Bump version to 2.4.0.
  Update changelog.
  Merge pull request #694 from mariusbuescher/master
  Add note about include and blocks; update wrapping of templating docs.
  Merge pull request #688 from pra85/patch-1
  Rename all test templates to use .j2 extension.
  Update changelog.
  Revert "make include statements trigger async conversion inside if/for statements (fixes #372)"
  Merge pull request #672 from TrySound/yargs
  Update changelog.
  Split backported and non-backported portions of #667 in changelog.
  More acks in changelog.
  Merge pull request #668 from oyyd/cn-doc
  Don't allow included templates to write to the including scope.
  Update changelog for opts.dev fix.
  Split include tests.
  Fix references to env dev opt.
  ...

* master: (88 commits)
  Bump versions for dev.
  Update maintenance docs.
  Revert accidental changes to mocha.js.
  Bump version to 2.4.0.
  Update changelog.
  Merge pull request #694 from mariusbuescher/master
  Update changelog.
  Add support for boolean globals
  Add note about include and blocks; update wrapping of templating docs.
  Merge pull request #688 from pra85/patch-1
  Add note about include and blocks; update wrapping of templating docs.
  Update api.md
  fixed bad character leading % in {% endraw %}
  Respect null/none as a value in its own right, distinct from undefined. Fixes #478.
  Use dot reporter for npm test.
  Don't bail on first failed test in 'npm test'.
  Add acknowledgement for #561 to changelog.
  Tighter scoping of vars in blocks, to match Jinja2. Fixes #561.
  Rename all test templates to use .j2 extension.
  Rename all test templates to use .j2 extension.
  ...